Use requestAnimationFrame
Use a properties hash in the constructor instead of list of arguments.
Convert tabs to spaces.
CSS overhaul.
Extract canvas drawing logic into own clas, CanvasDrawer.
Namespace utility methods instead of cluttering the Asteroids object.
Refactor game/ship/asteroid.
Refactoring.
Big refactor.
Increase max ship speed.
Rename files.
Add screenshot, update README.