diff --git a/lib/cyberarm_engine/window.rb b/lib/cyberarm_engine/window.rb
index 510bfb5..9c98ffe 100644
--- a/lib/cyberarm_engine/window.rb
+++ b/lib/cyberarm_engine/window.rb
@@ -1,5 +1,7 @@
 module CyberarmEngine
   class Window < Gosu::Window
+    include Common
+
     IMAGES = {}
     SAMPLES = {}
     SONGS = {}