Technical notes: The background has been overlayed with a dirty texture to prevent it from looking flat. There is actually no performance penalty for doing this in Flash because the background can just be flagged to be cached as a bitmap, which occurs in memory after the first render. This also means that the dirty texture is stored only once in the swf file. Of course on mobile devices, everything is a bitmap anyways... I estimate that three screens worth of background art can be squeezed into a single 1024x1024 texture with reasonable quality.