This is a very basic game, I mean the concept works quite well, but I have a few issues with the design choices. The background for one is very off putting, something static, or easier to look at would be much nicer, and wouldn't cause headaches! Additionally, you could do something about the thing you play as, maybe change it into a ship, or give it a little more character, as is, it's just a bland triangle.
There are other things you could do, like change the music when you switch, have some checkpoint pads, so if you die, you end up back there, and the score/time could also be easier to read. As it is, I don't think it's a bad game, just needs some work.