Good Concept
I enjoyed the concept thoroughly and the art was good. It did kind of get monotonous though.
If you're looking for ideas on how to add more diversity to this game (not that you need to), I'll offer a few. You could have the laser destroy other colors but with a penalty to the score. Another idea would be to have different color meteors absorb the laser. (although, this idea would work better if the laser was coming from one side of the window rather than both sides) You could give larger meteors more health per se (kind of like Asteroids). Anyways, you probably have better ideas than me.
Coaly already mentioned the severe lag part. For this type of game, you could definitely use the copyPixel method of drawing to the screen to speed things up. It does take some learning though. And you'd be working with bitmaps rather than 3D objects if you were using a 3D renderer.
Keep up the good work.