diff --git a/Building.md b/Building.md
index 60512f0..442897c 100644
--- a/Building.md
+++ b/Building.md
@@ -15,6 +15,7 @@
   - [Build on macOS from scratch](#build-on-macos-from-scratch)
 - [WebAssembly](#webassembly)
 - [Build Tags](#build-tags)
+  - [doodad](#doodad)
   - [dpp](#dpp)
 
 # Dockerfile
@@ -373,6 +374,13 @@ Some tips to get a WASM build to work:
 
 Go build tags used by this game:
 
+## doodad
+
+This tag is used when building the `doodad` command-line tool.
+
+It ensures that the embedded bindata assets (built-in doodads, etc.) do not
+need to be bundled into the doodad binary, but only the main game binary.
+
 ## dpp
 
 The dpp tag stands for Doodle++ and is used for official commercial builds of
diff --git a/Makefile b/Makefile
index 0efce21..8fb40ca 100644
--- a/Makefile
+++ b/Makefile
@@ -23,7 +23,7 @@ setup: clean
 .PHONY: build
 build:
 	go build $(LDFLAGS) $(BUILD_TAGS) -o bin/sketchymaze cmd/doodle/main.go
-	go build $(LDFLAGS) $(BUILD_TAGS) -o bin/doodad cmd/doodad/main.go
+	go build $(LDFLAGS) -tags=doodad -o bin/doodad cmd/doodad/main.go
 
 # `make buildall` to run all build steps including doodads.
 .PHONY: buildall
@@ -34,7 +34,7 @@ buildall: doodads build
 build-free:
 	gofmt -w .
 	go build $(LDFLAGS) -o bin/sketchymaze cmd/doodle/main.go
-	go build $(LDFLAGS) -o bin/doodad cmd/doodad/main.go
+	go build $(LDFLAGS) -tags=doodad -o bin/doodad cmd/doodad/main.go
 
 # `make bindata` generates the embedded binary assets package.
 .PHONY: bindata
@@ -75,7 +75,7 @@ mingw:
 		go build $(LDFLAGS_W) $(BUILD_TAGS) -o bin/sketchymaze.exe cmd/doodle/main.go
 	env CGO_ENABLED="1" CC="/usr/bin/x86_64-w64-mingw32-gcc" \
 		GOOS="windows" CGO_LDFLAGS="-lmingw32 -lSDL2" CGO_CFLAGS="-D_REENTRANT" \
-		go build $(LDFLAGS) $(BUILD_TAGS) -o bin/doodad.exe cmd/doodad/main.go
+		go build $(LDFLAGS) -tags=doodad -o bin/doodad.exe cmd/doodad/main.go
 
 # `make mingw32` to cross-compile a Windows binary with mingw (32-bit).
 .PHONY: mingw32
@@ -85,7 +85,7 @@ mingw32:
 		go build $(LDFLAGS_W) $(BUILD_TAGS) -o bin/sketchymaze.exe cmd/doodle/main.go
 	env CGO_ENABLED="1" CC="/usr/bin/i686-w64-mingw32-gcc" \
 		GOOS="windows" CGO_LDFLAGS="-lmingw32 -lSDL2" CGO_CFLAGS="-D_REENTRANT" \
-		go build $(LDFLAGS) $(BUILD_TAGS) -o bin/doodad.exe cmd/doodad/main.go
+		go build $(LDFLAGS) -tags=doodad -o bin/doodad.exe cmd/doodad/main.go
 
 # `make mingw-free` for Windows binary in free mode.
 .PHONY: mingw-free
@@ -95,7 +95,7 @@ mingw-free:
 		go build $(LDFLAGS_W) -o bin/sketchymaze.exe cmd/doodle/main.go
 	env CGO_ENABLED="1" CC="/usr/bin/x86_64-w64-mingw32-gcc" \
 		GOOS="windows" CGO_LDFLAGS="-lmingw32 -lSDL2" CGO_CFLAGS="-D_REENTRANT" \
-		go build $(LDFLAGS) -o bin/doodad.exe cmd/doodad/main.go
+		go build $(LDFLAGS) -tags=doodad -o bin/doodad.exe cmd/doodad/main.go
 
 # `make release` runs the release.sh script, must be run
 # after `make dist`
diff --git a/assets/assets_embed.go b/assets/assets_embed.go
index ac18c67..2a73cda 100644
--- a/assets/assets_embed.go
+++ b/assets/assets_embed.go
@@ -1,3 +1,6 @@
+//go:build !doodad
+// +build !doodad
+
 // Package assets gets us off go-bindata by using Go 1.16 embed support.
 //
 // For Go 1.16 embed, this source file had to live inside the assets/ folder
diff --git a/assets/assets_omitted.go b/assets/assets_omitted.go
new file mode 100644
index 0000000..7f94524
--- /dev/null
+++ b/assets/assets_omitted.go
@@ -0,0 +1,32 @@
+//go:build doodad
+// +build doodad
+
+// Dummy version of assets_embed.go that doesn't embed any files.
+// For the `doodad` tool.
+
+package assets
+
+import (
+	"embed"
+	"errors"
+)
+
+var Embedded embed.FS
+
+var errNotEmbedded = errors.New("assets not embedded")
+
+// AssetDir returns the list of embedded files at the directory name.
+func AssetDir(name string) ([]string, error) {
+	return nil, errNotEmbedded
+}
+
+// Asset returns the byte data of an embedded asset.
+func Asset(name string) ([]byte, error) {
+	return nil, errNotEmbedded
+}
+
+// AssetNames dumps the names of all embedded assets,
+// with their legacy "assets/" prefix from go-bindata.
+func AssetNames() []string {
+	return nil
+}
diff --git a/cmd/doodad/commands/resave.go b/cmd/doodad/commands/resave.go
index 495b162..e317c2b 100644
--- a/cmd/doodad/commands/resave.go
+++ b/cmd/doodad/commands/resave.go
@@ -101,6 +101,12 @@ func resaveDoodad(c *cli.Context, filename string) error {
 		filename = output
 	}
 
+	if err := dd.Vacuum(); err != nil {
+		log.Error("Vacuum error: %s", err)
+	} else {
+		log.Info("Run vacuum on doodad file.")
+	}
+
 	log.Info("Saving back to disk")
 	if err := dd.WriteJSON(filename); err != nil {
 		return fmt.Errorf("couldn't write %s: %s", filename, err)
diff --git a/pkg/branding/branding.go b/pkg/branding/branding.go
index 1c2a332..cad8053 100644
--- a/pkg/branding/branding.go
+++ b/pkg/branding/branding.go
@@ -9,7 +9,7 @@ import (
 const (
 	AppName   = "Sketchy Maze"
 	Summary   = "A drawing-based maze game"
-	Version   = "0.14.0"
+	Version   = "0.14.1"
 	Website   = "https://www.sketchymaze.com"
 	Copyright = "2023 Noah Petherbridge"
 	Byline    = "a game by Noah Petherbridge."
diff --git a/pkg/doodads/fmt_maintenance.go b/pkg/doodads/fmt_maintenance.go
new file mode 100644
index 0000000..9b3099b
--- /dev/null
+++ b/pkg/doodads/fmt_maintenance.go
@@ -0,0 +1,14 @@
+package doodads
+
+// Vacuum runs any maintenance or migration tasks for the level at time of save.
+//
+// It will prune broken links between actors, or migrate internal data structures
+// to optimize storage on disk of its binary data.
+func (m *Doodad) Vacuum() error {
+	// Let the Chunker optimize accessor types.
+	for _, layer := range m.Layers {
+		layer.Chunker.OptimizeChunkerAccessors()
+	}
+
+	return nil
+}
diff --git a/pkg/doodads/fmt_readwrite.go b/pkg/doodads/fmt_readwrite.go
index a50ae80..3d8e0bb 100644
--- a/pkg/doodads/fmt_readwrite.go
+++ b/pkg/doodads/fmt_readwrite.go
@@ -164,6 +164,11 @@ func (d *Doodad) WriteFile(filename string) error {
 	d.Version = 1
 	d.GameVersion = branding.Version
 
+	// Maintenance functions, clean up cruft before save.
+	if err := d.Vacuum(); err != nil {
+		log.Error("Vacuum level %s: %s", filename, err)
+	}
+
 	bin, err := d.ToJSON()
 	if err != nil {
 		return err
diff --git a/pkg/level/chunker_migrate.go b/pkg/level/chunker_migrate.go
index 5b70fe2..60fce35 100644
--- a/pkg/level/chunker_migrate.go
+++ b/pkg/level/chunker_migrate.go
@@ -36,8 +36,11 @@ func (c *Chunker) OptimizeChunkerAccessors() {
 						ma, _ := chunk.Accessor.(*MapAccessor)
 						rle := NewRLEAccessor(chunk).FromMapAccessor(ma)
 
+						// Lock the chunker for updating.
+						c.chunkMu.Lock()
 						c.Chunks[point].Type = RLEType
 						c.Chunks[point].Accessor = rle
+						c.chunkMu.Unlock()
 					}
 				}
 			}