diff --git a/scenes/file_browser.gd b/scenes/file_browser.gd
index 906c026..2076747 100644
--- a/scenes/file_browser.gd
+++ b/scenes/file_browser.gd
@@ -48,6 +48,8 @@ func update():
 		wd_files.pop_back()
 		wd_files = helpers.map(wd_files, self, "substr2")
 		
+		var files = wd_files
+		
 		var head_files
 		var index_files
 		
@@ -61,13 +63,12 @@ func update():
 			# The last entry is an empty string, remove it.
 			index_files.pop_back()
 		
-		var files = wd_files
-		for f in head_files:
-			if not f in files:
-				files.push_back(f)
-		for f in index_files:
-			if not f in files:
-				files.push_back(f)
+			for f in head_files:
+				if not f in files:
+					files.push_back(f)
+			for f in index_files:
+				if not f in files:
+					files.push_back(f)
 				
 		files.sort_custom(self, "very_best_sort")
 		
diff --git a/scenes/game.gd b/scenes/game.gd
index 412d11d..9728efc 100644
--- a/scenes/game.gd
+++ b/scenes/game.gd
@@ -28,7 +28,7 @@ func copy_script_to_game_env(name):
 	global_shell.run("chmod u+x '%s'" % (tmp_prefix + name))
 	
 func _initial_state():
-	return {"history": []}
+	return {"history": [], "solved_levels": []}
 	
 func save_state():
 	var savegame = File.new()
diff --git a/scenes/level_select.gd b/scenes/level_select.gd
index 18def77..026a640 100644
--- a/scenes/level_select.gd
+++ b/scenes/level_select.gd
@@ -36,6 +36,11 @@ func reload():
 			b.text = level.title
 			b.align = HALIGN_LEFT
 			b.connect("pressed", self, "load", [chapter_id, level_id])
+			var slug = chapter.slug + "/" + level.slug
+			if slug in game.state["solved_levels"]:
+				b.set("custom_colors/font_color", Color(0.1, 0.8, 0.1, 1))
+				b.set("custom_colors/font_color_hover", Color(0.1, 0.8, 0.1, 1))
+				b.set("custom_colors/font_color_pressed", Color(0.1, 0.8, 0.1, 1))
 			level_list.add_child(b)
 			level_id += 1
 			
diff --git a/scenes/main.gd b/scenes/main.gd
index d4e4a5d..3fa3a30 100644
--- a/scenes/main.gd
+++ b/scenes/main.gd
@@ -143,6 +143,12 @@ func show_win_status(win_states):
 		level_description.hide()
 		level_congrats.show()
 		$SuccessSound.play()
+		if not game.state.has("solved_levels"):
+			game.state["solved_levels"] = []
+		var slug = levels.chapters[game.current_chapter].slug + "/" + level.slug
+		if not slug in game.state["solved_levels"]:
+			game.state["solved_levels"].push_back(slug)
+			game.save_state()
 
 func repopulate_levels():
 	levels.reload()