I've added lots of things since my last post:

...Unfortunately, I tested the game on the iPad, and found that Mobile Safari is very slow at rendering image masks. This is bad, because I use image masking to display ALL sprites. I think I will fork development here and try a new strategy. Perhaps I will make a sprite sheet for EVERY color combination (and mirror!) needed for every sprite. Wish me good luck!

PS: As a bonus, this will make game will work in FF and perhaps even IE!