Asteroids is always a good choice for an HTML5/mobile game. There's lots of possibilities and nearly infinite gameplay variety. This one looks pretty good -- although it also seems fairly standard. The graphics are OK, but you've added some neat particle effects for the explosions. So that's fun.
However, I recommend you re-write the particle code to simplify it and/or make it more efficient. Because it causes a short delay when the asteroids are hit. Not a big delay... but it's noticeable. So I'd start by using fewer
particles -- or replace the particles by 3-4 small custom sprites that show "fragments". Also, make sure that the particles are defined once
at the beginning, instead of having each asteroid re-define its own particles.
You might also consider changing the star background. Specifically, make it a bit irregular instead of the uniform star pattern. Also, make the stars look different than the bullets, so the bullets stand out more against the background.
I think with a few tweaks and some optimization, you'll have a really good Asteroids game here.
Edited by chance, 23 December 2012 - 12:19 PM.