diff --git a/dev-assets/doodads/azulian/azulian-red.js b/dev-assets/doodads/azulian/azulian-red.js
deleted file mode 100644
index aeb5f91..0000000
--- a/dev-assets/doodads/azulian/azulian-red.js
+++ /dev/null
@@ -1,43 +0,0 @@
-// Azulian (Red)
-// DEPRECATED: they both share azulian.js now.
-
-function main() {
-	var playerSpeed = 4;
-	var gravity = 4;
-	var Vx = Vy = 0;
-
-	var direction = "right";
-
-	Self.SetHitbox(0, 0, 32, 32)
-	Self.SetMobile(true);
-	Self.SetInventory(true);
-	Self.SetGravity(true);
-	Self.AddAnimation("walk-left", 100, ["red-wl1", "red-wl2", "red-wl3", "red-wl4"]);
-	Self.AddAnimation("walk-right", 100, ["red-wr1", "red-wr2", "red-wr3", "red-wr4"]);
-
-	// Sample our X position every few frames and detect if we've hit a solid wall.
-	var sampleTick = 0;
-	var sampleRate = 5;
-	var lastSampledX = 0;
-
-	setInterval(function () {
-		if (sampleTick % sampleRate === 0) {
-			var curX = Self.Position().X;
-			var delta = Math.abs(curX - lastSampledX);
-			if (delta < 5) {
-				direction = direction === "right" ? "left" : "right";
-			}
-			lastSampledX = curX;
-		}
-		sampleTick++;
-
-		// TODO: Vector() requires floats, pain in the butt for JS,
-		// the JS API should be friendlier and custom...
-		var Vx = parseFloat(playerSpeed * (direction === "left" ? -1 : 1));
-		Self.SetVelocity(Vector(Vx, 0.0));
-
-		if (!Self.IsAnimating()) {
-			Self.PlayAnimation("walk-" + direction, null);
-		}
-	}, 100);
-}
diff --git a/dev-assets/doodads/azulian/azulian.js b/dev-assets/doodads/azulian/azulian.js
index bd63b64..fb4dacb 100644
--- a/dev-assets/doodads/azulian/azulian.js
+++ b/dev-assets/doodads/azulian/azulian.js
@@ -5,7 +5,7 @@ var playerSpeed = 12,
 	lastDirection = "right";
 
 function setupAnimations(color) {
-	var left = color === 'blue' ? 'blu-wl' : 'red-wl',
+	let left = color === 'blue' ? 'blu-wl' : 'red-wl',
 		right = color === 'blue' ? 'blu-wr' : 'red-wr',
 		leftFrames = [left + '1', left + '2', left + '3', left + '4'],
 		rightFrames = [right + '1', right + '2', right + '3', right + '4'];
@@ -15,7 +15,7 @@ function setupAnimations(color) {
 }
 
 function main() {
-	var color = Self.GetTag("color");
+	const color = Self.GetTag("color");
 	playerSpeed = color === 'blue' ? 2 : 4;
 
 	Self.SetMobile(true);
@@ -32,14 +32,14 @@ function main() {
 	// when it meets resistance.
 
 	// Sample our X position every few frames and detect if we've hit a solid wall.
-	var sampleTick = 0;
-	var sampleRate = 5;
-	var lastSampledX = 0;
+	let sampleTick = 0;
+	let sampleRate = 5;
+	let lastSampledX = 0;
 
-	setInterval(function () {
+	setInterval(() => {
 		if (sampleTick % sampleRate === 0) {
-			var curX = Self.Position().X;
-			var delta = Math.abs(curX - lastSampledX);
+			let curX = Self.Position().X;
+			let delta = Math.abs(curX - lastSampledX);
 			if (delta < 5) {
 				direction = direction === "right" ? "left" : "right";
 			}
@@ -47,7 +47,7 @@ function main() {
 		}
 		sampleTick++;
 
-		var Vx = parseFloat(playerSpeed * (direction === "left" ? -1 : 1));
+		let Vx = parseFloat(playerSpeed * (direction === "left" ? -1 : 1));
 		Self.SetVelocity(Vector(Vx, 0.0));
 
 		// If we changed directions, stop animating now so we can
@@ -66,7 +66,7 @@ function main() {
 
 function playerControls() {
 	// Note: player speed is controlled by the engine.
-	Events.OnKeypress(function (ev) {
+	Events.OnKeypress((ev) => {
 		if (ev.Right) {
 			if (!Self.IsAnimating()) {
 				Self.PlayAnimation("walk-right", null);
diff --git a/dev-assets/doodads/bird/bird.js b/dev-assets/doodads/bird/bird.js
index c47b628..1a03356 100644
--- a/dev-assets/doodads/bird/bird.js
+++ b/dev-assets/doodads/bird/bird.js
@@ -1,17 +1,17 @@
 // Bird
 
 function main() {
-	var speed = 4;
-	var Vx = Vy = 0;
-	var altitude = Self.Position().Y; // original height in the level
+	let speed = 4,
+		Vx = Vy = 0,
+		altitude = Self.Position().Y; // original height in the level
 
-	var direction = "left",
+	let direction = "left",
 		lastDirection = "left";
-	var states = {
+	let states = {
 		flying: 0,
 		diving: 1,
 	};
-	var state = states.flying;
+	let state = states.flying;
 
 	Self.SetMobile(true);
 	Self.SetGravity(false);
@@ -24,22 +24,22 @@ function main() {
 		return player();
 	}
 
-	Events.OnCollide(function (e) {
+	Events.OnCollide((e) => {
 		if (e.Actor.IsMobile() && e.InHitbox) {
 			return false;
 		}
 	});
 
 	// Sample our X position every few frames and detect if we've hit a solid wall.
-	var sampleTick = 0;
-	var sampleRate = 2;
-	var lastSampledX = 0;
-	var lastSampledY = 0;
+	let sampleTick = 0,
+		sampleRate = 2,
+		lastSampledX = 0,
+		lastSampledY = 0;
 
-	setInterval(function () {
+	setInterval(() => {
 		if (sampleTick % sampleRate === 0) {
-			var curX = Self.Position().X;
-			var delta = Math.abs(curX - lastSampledX);
+			let curX = Self.Position().X;
+			let delta = Math.abs(curX - lastSampledX);
 			if (delta < 5) {
 				direction = direction === "right" ? "left" : "right";
 			}
@@ -48,15 +48,15 @@ function main() {
 		sampleTick++;
 
 		// If we are not flying at our original altitude, correct for that.
-		var curV = Self.Position();
-		var Vy = 0.0;
+		let curV = Self.Position();
+		let Vy = 0.0;
 		if (curV.Y != altitude) {
 			Vy = curV.Y < altitude ? 1 : -1;
 		}
 
 		// TODO: Vector() requires floats, pain in the butt for JS,
 		// the JS API should be friendlier and custom...
-		var Vx = parseFloat(speed * (direction === "left" ? -1 : 1));
+		let Vx = parseFloat(speed * (direction === "left" ? -1 : 1));
 		Self.SetVelocity(Vector(Vx, Vy));
 
 		// If we changed directions, stop animating now so we can
@@ -76,7 +76,7 @@ function main() {
 // If under control of the player character.
 function player() {
 	Self.SetInventory(true);
-	Events.OnKeypress(function (ev) {
+	Events.OnKeypress((ev) => {
 		Vx = 0;
 		Vy = 0;
 
@@ -103,4 +103,4 @@ function player() {
 
 		Self.SetVelocity(Vector(Vx, Vy));
 	})
-}
\ No newline at end of file
+}
diff --git a/dev-assets/doodads/box/box.js b/dev-assets/doodads/box/box.js
index 30d3d6a..5a68e85 100644
--- a/dev-assets/doodads/box/box.js
+++ b/dev-assets/doodads/box/box.js
@@ -1,20 +1,21 @@
 // Pushable Box.
-var speed = 4;
-var size = 75;
+
+const speed = 4,
+    size = 75;
 
 function main() {
     Self.SetMobile(true);
     Self.SetGravity(true);
     Self.SetHitbox(0, 0, size, size);
 
-    Events.OnCollide(function (e) {
+    Events.OnCollide((e) => {
         // Ignore events from neighboring Boxes.
         if (e.Actor.Actor.Filename === "box.doodad") {
             return false;
         }
 
         if (e.Actor.IsMobile() && e.InHitbox) {
-            var overlap = e.Overlap;
+            let overlap = e.Overlap;
 
             if (overlap.Y === 0 && !(overlap.X === 0 && overlap.W < 5) && !(overlap.X === size)) {
                 // Standing on top, ignore.
@@ -39,8 +40,8 @@ function main() {
     });
 
     // When we receive power, we reset to our original position.
-    var origPoint = Self.Position();
-    Message.Subscribe("power", function (powered) {
+    let origPoint = Self.Position();
+    Message.Subscribe("power", (powered) => {
         Self.MoveTo(origPoint);
         Self.SetVelocity(Vector(0, 0));
     });
@@ -52,8 +53,8 @@ function main() {
 function animate() {
     Self.AddAnimation("animate", 100, [0, 1, 2, 3, 2, 1]);
 
-    var running = false;
-    setInterval(function () {
+    let running = false;
+    setInterval(() => {
         if (!running) {
             running = true;
             Self.PlayAnimation("animate", function () {
@@ -61,4 +62,4 @@ function animate() {
             })
         }
     }, 100);
-}
\ No newline at end of file
+}
diff --git a/dev-assets/doodads/boy/boy.js b/dev-assets/doodads/boy/boy.js
index 8c9f532..6b087e5 100644
--- a/dev-assets/doodads/boy/boy.js
+++ b/dev-assets/doodads/boy/boy.js
@@ -1,10 +1,10 @@
+const playerSpeed = 12;
+
+let Vx = Vy = 0,
+	animating = false,
+	animStart = animEnd = 0;
+
 function main() {
-	var playerSpeed = 12;
-	var Vx = Vy = 0;
-
-	var animating = false;
-	var animStart = animEnd = 0;
-
 	Self.SetMobile(true);
 	Self.SetInventory(true);
 	Self.SetGravity(true);
@@ -13,13 +13,13 @@ function main() {
 	Self.AddAnimation("walk-right", 200, ["stand-right", "walk-right-1", "walk-right-2", "walk-right-3", "walk-right-2", "walk-right-1"]);
 
 	// If the player suddenly changes direction, reset the animation state to quickly switch over.
-	var lastVelocity = Vector(0, 0);
+	let lastVelocity = Vector(0, 0);
 
-	Events.OnKeypress(function (ev) {
+	Events.OnKeypress((ev) => {
 		Vx = 0;
 		Vy = 0;
 
-		var curVelocity = Self.GetVelocity();
+		let curVelocity = Self.GetVelocity();
 		if ((lastVelocity.X < 0 && curVelocity.X > 0) ||
 			(lastVelocity.X > 0 && curVelocity.X < 0)) {
 			Self.StopAnimation();
@@ -40,7 +40,5 @@ function main() {
 			Self.StopAnimation();
 			animating = false;
 		}
-
-		// Self.SetVelocity(Point(Vx, Vy));
 	})
 }
diff --git a/dev-assets/doodads/buttons/button.js b/dev-assets/doodads/buttons/button.js
index 500af52..a07bba2 100644
--- a/dev-assets/doodads/buttons/button.js
+++ b/dev-assets/doodads/buttons/button.js
@@ -1,18 +1,18 @@
 function main() {
-	var timer = 0;
-	var pressed = false;
+	let timer = 0;
+	let pressed = false;
 
 	// Has a linked Sticky Button been pressed permanently down?
-	var stickyDown = false;
-	Message.Subscribe("sticky:down", function (down) {
+	let stickyDown = false;
+	Message.Subscribe("sticky:down", (down) => {
 		stickyDown = down;
 		Self.ShowLayer(stickyDown ? 1 : 0);
 	});
 
 	// Track who all is colliding with us.
-	var colliders = {};
+	let colliders = {};
 
-	Events.OnCollide(function (e) {
+	Events.OnCollide((e) => {
 		if (!e.Settled) {
 			return;
 		}
@@ -46,7 +46,7 @@ function main() {
 		Self.ShowLayer(1);
 	});
 
-	Events.OnLeave(function (e) {
+	Events.OnLeave((e) => {
 		delete colliders[e.Actor.ID()];
 
 		if (Object.keys(colliders).length === 0 && !stickyDown) {
diff --git a/dev-assets/doodads/buttons/sticky.js b/dev-assets/doodads/buttons/sticky.js
index 1702f8c..e9d6866 100644
--- a/dev-assets/doodads/buttons/sticky.js
+++ b/dev-assets/doodads/buttons/sticky.js
@@ -1,8 +1,8 @@
 function main() {
-	var pressed = false;
+	let pressed = false;
 
 	// When a sticky button receives power, it pops back up.
-	Message.Subscribe("power", function (powered) {
+	Message.Subscribe("power", (powered) => {
 		if (powered && pressed) {
 			Self.ShowLayer(0);
 			pressed = false;
@@ -12,7 +12,7 @@ function main() {
 		}
 	})
 
-	Events.OnCollide(function (e) {
+	Events.OnCollide((e) => {
 		if (!e.Settled) {
 			return;
 		}
diff --git a/dev-assets/doodads/crumbly-floor/crumbly-floor.js b/dev-assets/doodads/crumbly-floor/crumbly-floor.js
index c7bdf08..283bd65 100644
--- a/dev-assets/doodads/crumbly-floor/crumbly-floor.js
+++ b/dev-assets/doodads/crumbly-floor/crumbly-floor.js
@@ -6,19 +6,16 @@ function main() {
 	Self.AddAnimation("fall", 100, ["fall1", "fall2", "fall3", "fall4"]);
 
 	// Recover time for the floor to respawn.
-	var recover = 5000;
+	let recover = 5000;
 
 	// States of the floor.
-	var stateSolid = 0;
-	var stateShaking = 1;
-	var stateFalling = 2;
-	var stateFallen = 3;
-	var state = stateSolid;
+	let stateSolid = 0;
+	let stateShaking = 1;
+	let stateFalling = 2;
+	let stateFallen = 3;
+	let state = stateSolid;
 
-	// Started the animation?
-	var startedAnimation = false;
-
-	Events.OnCollide(function(e) {
+	Events.OnCollide((e) => {
 
 		// If the floor is falling, the player passes right thru.
 		if (state === stateFalling || state === stateFallen) {
@@ -40,15 +37,15 @@ function main() {
 			// Begin the animation sequence if we're in the solid state.
 			if (state === stateSolid) {
 				state = stateShaking;
-				Self.PlayAnimation("shake", function() {
+				Self.PlayAnimation("shake", () => {
 					state = stateFalling;
-					Self.PlayAnimation("fall", function() {
+					Self.PlayAnimation("fall", () => {
 						Sound.Play("crumbly-break.wav")
 						state = stateFallen;
 						Self.ShowLayerNamed("fallen");
 
 						// Recover after a while.
-						setTimeout(function() {
+						setTimeout(() => {
 							Self.ShowLayer(0);
 							state = stateSolid;
 						}, recover);
diff --git a/dev-assets/doodads/doors/colored-door.js b/dev-assets/doodads/doors/colored-door.js
index 0bfba60..1c47ab6 100644
--- a/dev-assets/doodads/doors/colored-door.js
+++ b/dev-assets/doodads/doors/colored-door.js
@@ -1,9 +1,11 @@
-function main() {
-	var color = Self.GetTag("color");
-	var keyname = color === "small" ? "small-key.doodad" : "key-" + color + ".doodad";
+// Colored Locked Doors.
 
+const color = Self.GetTag("color"),
+	keyname = color === "small" ? "small-key.doodad" : "key-" + color + ".doodad";
+
+function main() {
 	// Layers in the doodad image.
-	var layer = {
+	let layer = {
 		closed: 0,
 		unlocked: 1,
 		right: 2,
@@ -11,13 +13,13 @@ function main() {
 	};
 
 	// Variables that change in event handler.
-	var unlocked = false;  // Key has been used to unlock the door (one time).
-	var opened = false;    // If door is currently showing its opened state.
-	var enterSide = 0;     // Side of player entering the door, -1 or 1, left or right.
+	let unlocked = false;  // Key has been used to unlock the door (one time).
+	let opened = false;    // If door is currently showing its opened state.
+	let enterSide = 0;     // Side of player entering the door, -1 or 1, left or right.
 
 	Self.SetHitbox(34, 0, 13, 76);
 
-	Events.OnCollide(function(e) {
+	Events.OnCollide((e) => {
 		// Record the side that this actor has touched us, in case the door
 		// needs to open.
 		if (enterSide === 0) {
@@ -37,7 +39,7 @@ function main() {
 			}
 
 			// Do they have our key?
-			var hasKey = e.Actor.HasItem(keyname) >= 0;
+			let hasKey = e.Actor.HasItem(keyname) >= 0;
 			if (!hasKey) {
 				// Door is locked.
 				return false;
@@ -55,7 +57,7 @@ function main() {
 			}
 		}
 	});
-	Events.OnLeave(function(e) {
+	Events.OnLeave((e) => {
 		Self.ShowLayer(unlocked ? layer.unlocked : layer.closed);
 		// Sound.Play("door-close.wav")
 
diff --git a/dev-assets/doodads/doors/electric-door.js b/dev-assets/doodads/doors/electric-door.js
index 127b812..c918a3b 100644
--- a/dev-assets/doodads/doors/electric-door.js
+++ b/dev-assets/doodads/doors/electric-door.js
@@ -1,6 +1,8 @@
-var animating = false;
-var opened = false;
-var powerState = false;
+// Electric Door
+
+let animating = false;
+let opened = false;
+let powerState = false;
 
 // Function to handle the door opening or closing.
 function setPoweredState(powered) {
@@ -13,14 +15,14 @@ function setPoweredState(powered) {
 
 		animating = true;
 		Sound.Play("electric-door.wav")
-		Self.PlayAnimation("open", function () {
+		Self.PlayAnimation("open", () => {
 			opened = true;
 			animating = false;
 		});
 	} else {
 		animating = true;
 		Sound.Play("electric-door.wav")
-		Self.PlayAnimation("close", function () {
+		Self.PlayAnimation("close", () => {
 			opened = false;
 			animating = false;
 		})
@@ -31,7 +33,6 @@ function main() {
 	Self.AddAnimation("open", 100, [0, 1, 2, 3]);
 	Self.AddAnimation("close", 100, [3, 2, 1, 0]);
 
-
 	Self.SetHitbox(0, 0, 34, 76);
 
 	// A linked Switch that activates the door will send the Toggle signal
@@ -39,13 +40,13 @@ function main() {
 	// state on this signal, and ignore the very next Power signal. Ordinary
 	// power sources like Buttons will work as normal, as they emit only a power
 	// signal.
-	var ignoreNextPower = false;
-	Message.Subscribe("switch:toggle", function (powered) {
+	let ignoreNextPower = false;
+	Message.Subscribe("switch:toggle", (powered) => {
 		ignoreNextPower = true;
 		setPoweredState(!powerState);
 	})
 
-	Message.Subscribe("power", function (powered) {
+	Message.Subscribe("power", (powered) => {
 		if (ignoreNextPower) {
 			ignoreNextPower = false;
 			return;
@@ -54,7 +55,7 @@ function main() {
 		setPoweredState(powered);
 	});
 
-	Events.OnCollide(function (e) {
+	Events.OnCollide((e) => {
 		if (e.InHitbox) {
 			if (!opened) {
 				return false;
diff --git a/dev-assets/doodads/doors/keys.js b/dev-assets/doodads/doors/keys.js
index 505f1e9..c51154d 100644
--- a/dev-assets/doodads/doors/keys.js
+++ b/dev-assets/doodads/doors/keys.js
@@ -1,8 +1,10 @@
-function main() {
-	var color = Self.GetTag("color");
-	var quantity = color === "small" ? 1 : 0;
+// Colored Keys and Small Key
 
-	Events.OnCollide(function (e) {
+const color = Self.GetTag("color"),
+	quantity = color === "small" ? 1 : 0;
+
+function main() {
+	Events.OnCollide((e) => {
 		if (e.Settled) {
 			if (e.Actor.HasInventory()) {
 				// If we don't have a quantity, and the actor already has
diff --git a/dev-assets/doodads/doors/locked-door.js b/dev-assets/doodads/doors/locked-door.js
deleted file mode 100644
index 820ae1a..0000000
--- a/dev-assets/doodads/doors/locked-door.js
+++ /dev/null
@@ -1,27 +0,0 @@
-// DEPRECATED: old locked door script. Superceded by colored-door.js.
-function main() {
-	Self.AddAnimation("open", 0, [1]);
-	var unlocked = false;
-	var color = Self.GetTag("color");
-
-	Self.SetHitbox(16, 0, 32, 64);
-
-	Events.OnCollide(function(e) {
-		if (unlocked) {
-			return;
-		}
-
-		if (e.InHitbox) {
-			var data = e.Actor.GetData("key:" + color);
-			if (data === "") {
-				// Door is locked.
-				return false;
-			}
-
-			if (e.Settled) {
-				unlocked = true;
-				Self.PlayAnimation("open", null);
-			}
-		}
-	});
-}
diff --git a/dev-assets/doodads/objects/anvil.js b/dev-assets/doodads/objects/anvil.js
index 2359bca..4390b98 100644
--- a/dev-assets/doodads/objects/anvil.js
+++ b/dev-assets/doodads/objects/anvil.js
@@ -8,9 +8,9 @@ function main() {
     Self.SetGravity(true);
 
     // Monitor our Y position to tell if we've been falling.
-    var lastPoint = Self.Position();
-    setInterval(function () {
-        var nowAt = Self.Position();
+    let lastPoint = Self.Position();
+    setInterval(() => {
+        let nowAt = Self.Position();
         if (nowAt.Y > lastPoint.Y) {
             falling = true;
         } else {
@@ -19,7 +19,7 @@ function main() {
         lastPoint = nowAt;
     }, 100);
 
-    Events.OnCollide(function (e) {
+    Events.OnCollide((e) => {
         if (!e.Settled) {
             return;
         }
@@ -43,8 +43,8 @@ function main() {
     });
 
     // When we receive power, we reset to our original position.
-    var origPoint = Self.Position();
-    Message.Subscribe("power", function (powered) {
+    let origPoint = Self.Position();
+    Message.Subscribe("power", (powered) => {
         Self.MoveTo(origPoint);
         Self.SetVelocity(Vector(0, 0));
     });
diff --git a/dev-assets/doodads/objects/checkpoint-flag.js b/dev-assets/doodads/objects/checkpoint-flag.js
index a50608a..4e74741 100644
--- a/dev-assets/doodads/objects/checkpoint-flag.js
+++ b/dev-assets/doodads/objects/checkpoint-flag.js
@@ -7,11 +7,11 @@ function main() {
 
     // Checkpoints broadcast to all of their peers so they all
     // know which one is the most recently activated.
-    Message.Subscribe("broadcast:checkpoint", function (currentID) {
+    Message.Subscribe("broadcast:checkpoint", (currentID) => {
         setActive(false);
     });
 
-    Events.OnCollide(function (e) {
+    Events.OnCollide((e) => {
         if (!e.Settled) {
             return;
         }
@@ -35,4 +35,4 @@ function setActive(v) {
 
     isCurrentCheckpoint = v;
     Self.ShowLayerNamed(v ? "checkpoint-active" : "checkpoint-inactive");
-}
\ No newline at end of file
+}
diff --git a/dev-assets/doodads/objects/exit-flag.js b/dev-assets/doodads/objects/exit-flag.js
index 9e65bf1..d45a754 100644
--- a/dev-assets/doodads/objects/exit-flag.js
+++ b/dev-assets/doodads/objects/exit-flag.js
@@ -2,7 +2,7 @@
 function main() {
 	Self.SetHitbox(22 + 16, 16, 75 - 16, 86);
 
-	Events.OnCollide(function (e) {
+	Events.OnCollide((e) => {
 		if (!e.Settled) {
 			return;
 		}
diff --git a/dev-assets/doodads/objects/start-flag.js b/dev-assets/doodads/objects/start-flag.js
index dc84a77..f215651 100644
--- a/dev-assets/doodads/objects/start-flag.js
+++ b/dev-assets/doodads/objects/start-flag.js
@@ -4,8 +4,7 @@ function main() {
 
     // Linking a doodad to the Start Flag sets the
     // player character. Destroy the original doodads.
-    var links = Self.GetLinks();
-    for (var i = 0; i < links.length; i++) {
-        links[i].Destroy();
+    for (var link of Self.GetLinks()) {
+        link.Destroy();
     }
 }
diff --git a/dev-assets/doodads/on-off/state-block-blue.js b/dev-assets/doodads/on-off/state-block-blue.js
index b754ea7..16e1421 100644
--- a/dev-assets/doodads/on-off/state-block-blue.js
+++ b/dev-assets/doodads/on-off/state-block-blue.js
@@ -3,9 +3,9 @@ function main() {
 	Self.SetHitbox(0, 0, 42, 42);
 
 	// Blue block is ON by default.
-	var state = true;
+	let state = true;
 
-	Message.Subscribe("broadcast:state-change", function(newState) {
+	Message.Subscribe("broadcast:state-change", (newState) => {
 		state = !newState;
 
 		// Layer 0: ON
@@ -13,7 +13,7 @@ function main() {
 		Self.ShowLayer(state ? 0 : 1);
 	});
 
-	Events.OnCollide(function(e) {
+	Events.OnCollide((e) => {
 		if (e.Actor.IsMobile() && e.InHitbox) {
 			if (state) {
 				return false;
diff --git a/dev-assets/doodads/on-off/state-block-orange.js b/dev-assets/doodads/on-off/state-block-orange.js
index 8989f73..7e3d518 100644
--- a/dev-assets/doodads/on-off/state-block-orange.js
+++ b/dev-assets/doodads/on-off/state-block-orange.js
@@ -3,9 +3,9 @@ function main() {
 	Self.SetHitbox(0, 0, 42, 42);
 
 	// Orange block is OFF by default.
-	var state = false;
+	let state = false;
 
-	Message.Subscribe("broadcast:state-change", function(newState) {
+	Message.Subscribe("broadcast:state-change", (newState) => {
 		state = newState;
 
 		// Layer 0: OFF
@@ -13,7 +13,7 @@ function main() {
 		Self.ShowLayer(state ? 1 : 0);
 	});
 
-	Events.OnCollide(function(e) {
+	Events.OnCollide((e) => {
 		if (e.Actor.IsMobile() && e.InHitbox) {
 			if (state) {
 				return false;
diff --git a/dev-assets/doodads/on-off/state-button.js b/dev-assets/doodads/on-off/state-button.js
index f0b02a6..291260c 100644
--- a/dev-assets/doodads/on-off/state-button.js
+++ b/dev-assets/doodads/on-off/state-button.js
@@ -1,23 +1,23 @@
 // State Block Control Button
 
 // Button is "OFF" by default.
-var state = false;
+let state = false;
 
 function main() {
 	Self.SetHitbox(0, 0, 42, 42);
 
 	// When the button is activated, don't keep toggling state until we're not
 	// being touched again.
-	var colliding = false;
+	let colliding = false;
 
 	// If we receive a state change event from a DIFFERENT on/off button, update
 	// ourself to match the state received.
-	Message.Subscribe("broadcast:state-change", function(value) {
+	Message.Subscribe("broadcast:state-change", (value) => {
 		state = value;
 		showSprite();
 	});
 
-	Events.OnCollide(function(e) {
+	Events.OnCollide((e) => {
 		if (colliding) {
 			return false;
 		}
@@ -40,7 +40,7 @@ function main() {
 		return false;
 	});
 
-	Events.OnLeave(function(e) {
+	Events.OnLeave((e) => {
 		colliding = false;
 	})
 }
diff --git a/dev-assets/doodads/regions/checkpoint.js b/dev-assets/doodads/regions/checkpoint.js
index 47f5669..1645f69 100644
--- a/dev-assets/doodads/regions/checkpoint.js
+++ b/dev-assets/doodads/regions/checkpoint.js
@@ -8,11 +8,11 @@ function main() {
 
     // Checkpoints broadcast to all of their peers so they all
     // know which one is the most recently activated.
-    Message.Subscribe("broadcast:checkpoint", function (currentID) {
+    Message.Subscribe("broadcast:checkpoint", (currentID) => {
         setActive(false);
     });
 
-    Events.OnCollide(function (e) {
+    Events.OnCollide((e) => {
         if (isCurrentCheckpoint || !e.Settled) {
             return;
         }
@@ -35,4 +35,4 @@ function setActive(v) {
     }
 
     isCurrentCheckpoint = v;
-}
\ No newline at end of file
+}
diff --git a/dev-assets/doodads/regions/fire.js b/dev-assets/doodads/regions/fire.js
index aae40c8..977537a 100644
--- a/dev-assets/doodads/regions/fire.js
+++ b/dev-assets/doodads/regions/fire.js
@@ -2,7 +2,7 @@
 function main() {
     Self.Hide();
 
-    Events.OnCollide(function (e) {
+    Events.OnCollide((e) => {
         if (!e.Settled) {
             return;
         }
diff --git a/dev-assets/doodads/regions/goal.js b/dev-assets/doodads/regions/goal.js
index 1d06f8f..6157c9d 100644
--- a/dev-assets/doodads/regions/goal.js
+++ b/dev-assets/doodads/regions/goal.js
@@ -2,7 +2,7 @@
 function main() {
     Self.Hide();
 
-    Events.OnCollide(function (e) {
+    Events.OnCollide((e) => {
         if (!e.Settled) {
             return;
         }
diff --git a/dev-assets/doodads/regions/power.js b/dev-assets/doodads/regions/power.js
index 072a526..6b555a3 100644
--- a/dev-assets/doodads/regions/power.js
+++ b/dev-assets/doodads/regions/power.js
@@ -15,7 +15,7 @@ function main() {
         );
     }
 
-    Message.Subscribe("broadcast:ready", function () {
+    Message.Subscribe("broadcast:ready", () => {
         Message.Publish("switch:toggle", true);
         Message.Publish("power", true);
     });
diff --git a/dev-assets/doodads/regions/stall.js b/dev-assets/doodads/regions/stall.js
index c174594..56cf5d4 100644
--- a/dev-assets/doodads/regions/stall.js
+++ b/dev-assets/doodads/regions/stall.js
@@ -4,7 +4,7 @@
 function main() {
     Self.Hide();
 
-    var active = true,
+    let active = true,
         timeout = 250,
         ms = Self.GetTag("ms");
 
@@ -12,7 +12,7 @@ function main() {
         timeout = parseInt(ms);
     }
 
-    Events.OnCollide(function (e) {
+    Events.OnCollide((e) => {
         if (!active || !e.Settled) {
             return;
         }
@@ -25,7 +25,7 @@ function main() {
         if (e.InHitbox) {
             // Grab hold of the player.
             e.Actor.Freeze();
-            setTimeout(function () {
+            setTimeout(() => {
                 e.Actor.Unfreeze();
             }, timeout);
 
@@ -34,7 +34,7 @@ function main() {
     });
 
     // Reset the trap if powered by a button.
-    Message.Subscribe("power", function (powered) {
+    Message.Subscribe("power", (powered) => {
         active = true;
     });
 }
diff --git a/dev-assets/doodads/switches/switch.js b/dev-assets/doodads/switches/switch.js
index 973a7b3..99fa153 100644
--- a/dev-assets/doodads/switches/switch.js
+++ b/dev-assets/doodads/switches/switch.js
@@ -4,15 +4,15 @@ function main() {
 	// 0: Off
 	// 1: On
 
-	var state = false;
-	var collide = false;
+	let state = false;
+	let collide = false;
 
-	Message.Subscribe("power", function (powered) {
+	Message.Subscribe("power", (powered) => {
 		state = powered;
 		showState(state);
 	});
 
-	Events.OnCollide(function (e) {
+	Events.OnCollide((e) => {
 		if (!e.Settled || !e.Actor.IsMobile()) {
 			return;
 		}
@@ -21,7 +21,6 @@ function main() {
 			Sound.Play("button-down.wav")
 			state = !state;
 
-			var nonce = Math.random() * 2147483647;
 			Message.Publish("switch:toggle", state);
 			Message.Publish("power", state);
 			showState(state);
@@ -30,7 +29,7 @@ function main() {
 		}
 	});
 
-	Events.OnLeave(function (e) {
+	Events.OnLeave((e) => {
 		collide = false;
 	});
 }
diff --git a/dev-assets/doodads/thief/thief.js b/dev-assets/doodads/thief/thief.js
index bdc945a..91ee6a7 100644
--- a/dev-assets/doodads/thief/thief.js
+++ b/dev-assets/doodads/thief/thief.js
@@ -21,8 +21,8 @@ function main() {
 // Common "steal" power between playable and A.I. thieves.
 function stealable() {
     // Steals your items.
-    Events.OnCollide(function (e) {
-        var victim = e.Actor;
+    Events.OnCollide((e) => {
+        let victim = e.Actor;
         if (!e.Settled) {
             return;
         }
@@ -33,17 +33,17 @@ function stealable() {
         }
 
         // Steal inventory
-        var stolen = 0;
+        let stolen = 0;
         if (victim.HasInventory()) {
-            var myInventory = Self.Inventory(),
+            let myInventory = Self.Inventory(),
                 theirInventory = victim.Inventory();
 
-            for (var key in theirInventory) {
+            for (let key in theirInventory) {
                 if (!theirInventory.hasOwnProperty(key)) {
                     continue;
                 }
 
-                var value = theirInventory[key];
+                let value = theirInventory[key];
                 if (value > 0 || myInventory[key] === undefined) {
                     victim.RemoveItem(key, value);
                     Self.AddItem(key, value);
@@ -68,7 +68,7 @@ function stealable() {
 // when it encounters and obstacle.
 function ai() {
     // Walks back and forth.
-    var Vx = Vy = 0.0,
+    let Vx = Vy = 0.0,
         playerSpeed = 4,
         direction = "right",
         lastDirection = "right",
@@ -76,9 +76,9 @@ function ai() {
         sampleTick = 0,
         sampleRate = 2;
 
-    setInterval(function () {
+    setInterval(() => {
         if (sampleTick % sampleRate === 0) {
-            var curX = Self.Position().X,
+            let curX = Self.Position().X,
                 delta = Math.abs(curX - lastSampledX);
             if (delta < 5) {
                 direction = direction === "right" ? "left" : "right";
@@ -106,7 +106,7 @@ function ai() {
 
 // If under control of the player character.
 function playable() {
-    Events.OnKeypress(function (ev) {
+    Events.OnKeypress((ev) => {
         Vx = 0;
         Vy = 0;
 
@@ -127,4 +127,4 @@ function playable() {
 
         // Self.SetVelocity(Point(Vx, Vy));
     })
-}
\ No newline at end of file
+}
diff --git a/dev-assets/doodads/trapdoors/down.js b/dev-assets/doodads/trapdoors/down.js
deleted file mode 100644
index 3ea5fba..0000000
--- a/dev-assets/doodads/trapdoors/down.js
+++ /dev/null
@@ -1,36 +0,0 @@
-function main() {
-	var timer = 0;
-
-	Self.SetHitbox(0, 0, 72, 6);
-
-	var animationSpeed = 100;
-	var opened = false;
-	Self.AddAnimation("open", animationSpeed, ["down1", "down2", "down3", "down4"]);
-	Self.AddAnimation("close", animationSpeed, ["down4", "down3", "down2", "down1"]);
-
-	Events.OnCollide( function(e) {
-		if (opened) {
-			return;
-		}
-
-		// Is the actor colliding our solid part?
-		if (e.InHitbox) {
-			// Touching the top or the bottom?
-			if (e.Overlap.Y > 0) {
-				return false; // solid wall when touched from below
-			} else {
-				opened = true;
-				Self.PlayAnimation("open", function() {
-				});
-			}
-		}
-	});
-
-	Events.OnLeave(function() {
-		if (opened) {
-			Self.PlayAnimation("close", function() {
-				opened = false;
-			});
-		}
-	})
-}
diff --git a/dev-assets/doodads/trapdoors/trapdoor.js b/dev-assets/doodads/trapdoors/trapdoor.js
index 54dca12..9bb6d70 100644
--- a/dev-assets/doodads/trapdoors/trapdoor.js
+++ b/dev-assets/doodads/trapdoors/trapdoor.js
@@ -1,12 +1,12 @@
+// Trapdoors.
+
+// What direction is the trapdoor facing?
+const direction = Self.GetTag("direction");
+
 function main() {
-	// What direction is the trapdoor facing?
-	var direction = Self.GetTag("direction");
-
-	var timer = 0;
-
 	// Set our hitbox based on our orientation.
-	var thickness = 10;
-	var doodadSize = 86;
+	let thickness = 10;
+	let doodadSize = 86;
 	if (direction === "left") {
 		Self.SetHitbox(48, 0, doodadSize, doodadSize);
 	} else if (direction === "right") {
@@ -17,12 +17,12 @@ function main() {
 		Self.SetHitbox(0, 0, doodadSize, thickness);
 	}
 
-	var animationSpeed = 100;
-	var opened = false;
+	let animationSpeed = 100;
+	let opened = false;
 
 	// Register our animations.
-	var frames = [];
-	for (var i = 1; i <= 4; i++) {
+	let frames = [];
+	for (let i = 1; i <= 4; i++) {
 		frames.push(direction + i);
 	}
 
@@ -30,7 +30,7 @@ function main() {
 	frames.reverse();
 	Self.AddAnimation("close", animationSpeed, frames);
 
-	Events.OnCollide( function(e) {
+	Events.OnCollide((e) => {
 		if (opened) {
 			return;
 		}
@@ -78,9 +78,9 @@ function main() {
 		}
 	});
 
-	Events.OnLeave(function() {
+	Events.OnLeave(() => {
 		if (opened) {
-			Self.PlayAnimation("close", function() {
+			Self.PlayAnimation("close", () => {
 				opened = false;
 			});
 		}
diff --git a/dev-assets/doodads/warp-door/warp-door.js b/dev-assets/doodads/warp-door/warp-door.js
index 10b587f..2bde9f3 100644
--- a/dev-assets/doodads/warp-door/warp-door.js
+++ b/dev-assets/doodads/warp-door/warp-door.js
@@ -1,16 +1,17 @@
 // Warp Doors
+
+const color = Self.GetTag("color"),
+	isStateDoor = color === 'blue' || color === 'orange';
+
+// State in case we're a blue warp door.
+let state = color === 'blue',
+	animating = false,
+	collide = false;
+
 function main() {
-	// Are we a blue or orange door? Regular warp door will be 'none'
-	var color = Self.GetTag("color");
-	var isStateDoor = color === 'blue' || color === 'orange';
-	var state = color === 'blue';  // Blue door is ON by default.
-
-	var animating = false;
-	var collide = false;
-
 	// Declare animations and sprite names.
-	var animSpeed = 100;
-	var spriteDefault, spriteDisabled;  // the latter for state doors.
+	let animSpeed = 100;
+	let spriteDefault, spriteDisabled;  // the latter for state doors.
 	if (color === 'blue') {
 		Self.AddAnimation("open", animSpeed, ["blue-2", "blue-3", "blue-4"]);
 		Self.AddAnimation("close", animSpeed, ["blue-4", "blue-3", "blue-2", "blue-1"]);
@@ -33,17 +34,17 @@ function main() {
 	}
 
 	// Find our linked Warp Door.
-	var links = Self.GetLinks()
-	var linkedDoor = null;
-	for (var i = 0; i < links.length; i++) {
-		if (links[i].Title.indexOf("Warp Door") > -1) {
-			linkedDoor = links[i];
+	let linkedDoor = null;
+	for (let link of Self.GetLinks()) {
+		if (link.Title.indexOf("Warp Door") > -1) {
+			linkedDoor = link;
+			break;
 		}
 	}
 
 	// Subscribe to the global state-change if we are a state door.
 	if (isStateDoor) {
-		Message.Subscribe("broadcast:state-change", function(newState) {
+		Message.Subscribe("broadcast:state-change", (newState) => {
 			state = color === 'blue' ? !newState : newState;
 
 			// Activate or deactivate the door.
@@ -52,12 +53,11 @@ function main() {
 	}
 
 	// For player groundedness work-around
-	var playerLastY = []; // last sampling of Y values
-	var lastUsed = time.Now();
+	let playerLastY = []; // last sampling of Y values
 
 	// The player Uses the door.
-	var flashedCooldown = false; // "Locked Door" flashed message.
-	Events.OnUse(function(e) {
+	let flashedCooldown = false; // "Locked Door" flashed message.
+	Events.OnUse((e) => {
 		if (animating) {
 			return;
 		}
@@ -86,7 +86,7 @@ function main() {
 				// Work-around: if two Boxes are stacked atop each other the player can
 				// get stuck if he jumps on top. He may not be Grounded but isn't changing
 				// effective Y position and a warp door may work as a good way out.
-				var yValue = e.Actor.Position().Y;
+				let yValue = e.Actor.Position().Y;
 
 				// Collect a sampling of last few Y values. If the player Y position
 				// is constant the last handful of frames, treat them as if they're
@@ -100,8 +100,8 @@ function main() {
 				playerLastY.pop();
 
 				// Hasn't moved?
-				var isGrounded = true;
-				for (var i = 0; i < playerLastY.length; i++) {
+				let isGrounded = true;
+				for (let i = 0; i < playerLastY.length; i++) {
 					if (yValue !== playerLastY[i]) {
 						isGrounded = false;
 						break;
@@ -120,9 +120,9 @@ function main() {
 
 			// Play the open and close animation.
 			animating = true;
-			Self.PlayAnimation("open", function() {
+			Self.PlayAnimation("open", () => {
 				e.Actor.Hide()
-				Self.PlayAnimation("close", function() {
+				Self.PlayAnimation("close", () => {
 					Self.ShowLayerNamed(isStateDoor && !state ? spriteDisabled : spriteDefault);
 					animating = false;
 
@@ -139,12 +139,12 @@ function main() {
 	});
 
 	// Respond to incoming warp events.
-	Message.Subscribe("warp-door:incoming", function(player) {
+	Message.Subscribe("warp-door:incoming", (player) => {
 		animating = true;
 		player.Unfreeze();
-		Self.PlayAnimation("open", function() {
+		Self.PlayAnimation("open", () => {
 			player.Show();
-			Self.PlayAnimation("close", function() {
+			Self.PlayAnimation("close", () => {
 				animating = false;
 
 				// If the receiving door was a State Door, fix its state.