diff --git a/Makefile b/Makefile
index 59d485c..a4a994c 100644
--- a/Makefile
+++ b/Makefile
@@ -1,8 +1,9 @@
 .PHONY: all
 
-COMMANDS: bin/script-decode
+all: bin/script-decode bin/sbutil
 
-all: $(COMMANDS)
-
-bin/%: cmd/%.go script/*.go
+bin/script-decode: cmd/script-decode.go script/*.go
+	go build -o $@ $<
+
+bin/sbutil: cmd/sbutil.go rom/*.go
 	go build -o $@ $<
diff --git a/cmd/script-decode.go b/cmd/script-decode.go
index 6edd828..04bde2d 100644
--- a/cmd/script-decode.go
+++ b/cmd/script-decode.go
@@ -58,7 +58,7 @@ func run(args *Arguments) error {
 	fmt.Fprintf(outfile, "; Stack address: $%04X\n\n", scr.StackAddress)
 
 	for _, token := range scr.Tokens {
-		fmt.Fprintln(outfile, token)
+		fmt.Fprintln(outfile, token.String(scr.Labels))
 	}
 
 	return nil
diff --git a/script/instructions.go b/script/instructions.go
index bc494a3..0329843 100644
--- a/script/instructions.go
+++ b/script/instructions.go
@@ -52,6 +52,8 @@ var Instructions []*Instruction = []*Instruction{
 	&Instruction{ 0x9B, 0, 0, 0,  "halt"},
 	&Instruction{ 0x9C, 0, 0, 0,  "toggle_44FE"},
 	&Instruction{ 0x9D, 2, 0, 0,  "something_tape"},
+
+	// Calls 0xEB draw_overlay.  Seems to draw a whole screen.
 	&Instruction{ 0x9E, 2, 0, 0,  ""},
 	&Instruction{ 0x9F, 6, 0, 0,  ""},
 
@@ -135,7 +137,14 @@ var Instructions []*Instruction = []*Instruction{
 	&Instruction{ 0xDA, 1, 0, 16, "to_int_string"},
 	&Instruction{ 0xDB, 3, 0, 0,  ""},
 	&Instruction{ 0xDC, 5, 0, 0,  ""},
-	&Instruction{ 0xDD, 5, 0, 0,  ""},
+
+	// ArgA, ArgB: X,Y of corner A
+	// ArgC, ArgD: X,Y of corner B
+	// ArgE: fill value.  This is an index into
+	//       the table at $B451.
+	// Fills a box with a tile
+	&Instruction{ 0xDD, 5, 0, 0,  "fill_box"},
+
 	&Instruction{ 0xDE, 3, 0, 0,  ""},
 	&Instruction{ 0xDF, 3, 0, 0,  ""},
 
@@ -153,7 +162,14 @@ var Instructions []*Instruction = []*Instruction{
 	&Instruction{ 0xE8, 1, 0, 0,  "setup_tape_nmi"},
 	&Instruction{ 0xE9, 0, 1, 0,  "setup_loop"},
 	&Instruction{ 0xEA, 0, 0, 0,  "string_write_to_table"},
-	&Instruction{ 0xEB, 4, 0, 0,  ""},
+
+	// Reads and saves tiles from the PPU, then draws over them.
+	// This is used to draw dialog boxes, so saving what it overwrites
+	// so it can re-draw them later makes sense.
+	// Not sure what the arguments actually mean.
+	// ArgB and ArgC are probably coordinates.
+	&Instruction{ 0xEB, 4, 0, 0,  "draw_overlay"},
+
 	&Instruction{ 0xEC, 2, 0, 0,  "scroll"},
 	&Instruction{ 0xED, 1, 0, 0,  "disable_sprites"},
 	&Instruction{ 0xEE, 1, -3, 0, "call_switch"},
diff --git a/script/parser.go b/script/parser.go
index 3a9e1a9..c223dc6 100644
--- a/script/parser.go
+++ b/script/parser.go
@@ -24,7 +24,9 @@ func Parse(rawinput []byte, startAddr int) (*Script, error) {
 		Warnings: []string{},
 		StackAddress: (int(rawinput[1])<<8) | int(rawinput[0]),
 		StartAddress: startAddr,
+		Labels: make(map[int]string), // map[location]name
 	}
+	tokenMap := make(map[int]*Token)
 
 	for i := 2; i < len(rawinput); i++ {
 		raw := rawinput[i]
@@ -35,6 +37,7 @@ func Parse(rawinput []byte, startAddr int) (*Script, error) {
 			Inline: []InlineVal{},
 		}
 		script.Tokens = append(script.Tokens, token)
+		tokenMap[token.Offset] = token
 
 		if raw < 0x80 {
 			continue
@@ -102,6 +105,7 @@ func Parse(rawinput []byte, startAddr int) (*Script, error) {
 				if tok.Offset == addr {
 					tok.IsTarget = true
 					found = true
+					script.Labels[addr] = fmt.Sprintf("L%04X", addr)
 					break
 				}
 			}
@@ -122,6 +126,7 @@ func Parse(rawinput []byte, startAddr int) (*Script, error) {
 					if tok.Offset == addr {
 						tok.IsTarget = true
 						found = true
+						script.Labels[addr] = fmt.Sprintf("L%04X", addr)
 						break
 					}
 				}
@@ -130,6 +135,19 @@ func Parse(rawinput []byte, startAddr int) (*Script, error) {
 					script.Warnings = append(script.Warnings, fmt.Sprintf("Warning: no target found for jump/call switch at offset $%04X; value: $%04X", t.Offset, addr))
 				}
 			}
+
+		default:
+			// if word arg, see if it's something in this script
+			if t.Instruction == nil {
+				continue
+			}
+			if t.Instruction.OpCount == 2 {
+				addr := t.Inline[0].Int()
+				if tok, ok := tokenMap[addr]; ok {
+					tok.IsVariable = true
+					script.Labels[addr] = fmt.Sprintf("Var_%04X", addr)
+				}
+			}
 		}
 	}
 
diff --git a/script/script.go b/script/script.go
index 81183df..ae8a2dc 100644
--- a/script/script.go
+++ b/script/script.go
@@ -9,4 +9,6 @@ type Script struct {
 
 	StartAddress int
 	StackAddress int
+
+	Labels map[int]string
 }
diff --git a/script/tokens.go b/script/tokens.go
index 1db8704..56a5d9b 100644
--- a/script/tokens.go
+++ b/script/tokens.go
@@ -9,12 +9,13 @@ type Token struct {
 	Offset   int
 	Raw      byte
 	Inline   []InlineVal
-	IsTarget bool // target of a call/jump?
+	IsTarget bool   // target of a call/jump?
+	IsVariable bool // target of something else
 
 	Instruction *Instruction
 }
 
-func (t Token) String() string {
+func (t Token) String(labels map[int]string) string {
 	suffix := ""
 	switch t.Raw {
 	case 0x86:
@@ -22,8 +23,12 @@ func (t Token) String() string {
 	}
 
 	prefix := ""
-	if t.IsTarget {
-		prefix = fmt.Sprintf("\nL%04X:\n", t.Offset)
+	if t.IsTarget || t.IsVariable {
+		if lbl, ok := labels[t.Offset]; ok {
+			prefix = "\n"+lbl+":\n"
+		} else {
+			prefix = fmt.Sprintf("\nL%04X:\n", t.Offset)
+		}
 	}
 
 	if t.Raw < 0x80 {
@@ -50,18 +55,26 @@ func (t Token) String() string {
 
 	argstr := []string{}
 	for _, a := range t.Inline {
-		argstr = append(argstr, a.HexString())
+		if lbl, ok := labels[a.Int()]; ok {
+			argstr = append(argstr, lbl)
+		} else {
+			argstr = append(argstr, a.HexString())
+		}
 	}
 
 	bytestr := []string{}
 	for _, a := range t.Inline {
 		for _, b := range a.Bytes() {
-			bytestr = append(bytestr, fmt.Sprintf("%02X", b))
+			//if lbl, ok := labels[a.Int()]; ok {
+			//	bytestr = append(bytestr, lbl)
+			//} else {
+				bytestr = append(bytestr, fmt.Sprintf("%02X", b))
+			//}
 		}
 	}
 
 	switch t.Raw {
-	case 0xBB:
+	case 0xBB: // push_data
 		bs := []byte{}
 		for _, val := range t.Inline {
 			bs = append(bs, val.Bytes()...)