Great idea!

I really like the idea. But, It'd be a lot better if there was a small story like "The asteroids are heading towards Earth! Slice them up before the enter our atmosphere!" or something like that.

The game would be a lot better with music. I'd pick something techno-y or rock-ish, but that's just my personal opinion. Music is a must, though. It really adds to the feel of the game.

Sometimes, I couldn't see the lazer when I fired it, which slightly frustrated me. The fact that a small bit of asteroid would be left after the bulk of it just blew up it also a tad frustrating. But, I liked the fact that you could deflect them with your ship. Maybe in an improved version, when you deflect the asteroids, they could pick up speed, catch on fire, and disappear. That'd be a nice touch.

The graphics could be better, but sometimes simple is better.

Overall, I really like the idea and the way the game plays. There are a few improvements to be made, though. The idea has a lot of potential. I'd really like to see this remade.

can go places

great and dont worry about the guy before me i understood the instructions.
also repouser is a word well its missing a "s" but it means to push away or repel.
meaning use the ship to bounce the asteroids off of it so you can have more time to slice them. so if your going to be a grammar Nazi at least know know what are words before you say there not real ones.

Functional, I suppose...

It's a shooter put together well enough, and the basic set pieces are functional. It's a bit irritating when a small asteroid piece approximately the size of four pixels keeps on flying toward you even after the bulk of it has been destroyed, though. It wouldn't be so bad if you could maneuver your ship more precisely, but as it is the laser is a little difficult to use precisely (ironically enough). Also you might want to check your spelling and grammar in the rules. I believe they should read:
"Use top/bottom arrows to move you ship.
Press space to fire your laser; the laser cannot be used while moving.
Slice asteroids until they disappear."
I can't even understand the sentence in TIPS, so you might want to take a look at that yourself: I'm pretty sure "repouser" is not a word...
Other than that, like I said it works fairly well as a basic side-scrolling shooter.