Right here.
RP1 is the first version, it's short, small, and simple. Use it if you have a slow machine.
RP2 is an experimental version with new features, but a terrible engine, causing serious lag. Play it only as an example of what NOT to do when making a game.
RP3.1 is the polished result of a weeks worth of work. I'm very proud of it.
RP3.5 is the latest, and greatest version. It's got everything 3.1 had, but more levels, an option to play forever, better sprecial effects, and a new enemy.
Here's the link:
http://www.alice.org/community/showthread.php?t=3205