Peeps Invaders was mad slow, and not intentionally so - it'd get even slower when three bullets were on the screen. Peeps Asteroids was ok at first, then got slow around level 5. I'm using an AMD 1.5 ghz. Both games start out way too easy, then get hard far too slowly.
So it's like, slow all around. I couldn't finish a game of either cause I got bored
I'd recommend dropping the quality on the sprites. There's no reason to have as much detail as is there, and flash is a piece of crap and can't handle it.
Oh, and in the original asteroids, you didn't slow down on your own, which was part of the challenge. It also doesn't really make sense to have your ship slow down on its own, since there's no friction in space. And it's a proven fact that there are peeps in space, so let's try to keep this as kosher as possible.