Not very well thought out, which is a shame because I got excited with the title. You just dodge asteroids. Your (one hit) hitbox includes the rainbow and even expands way beyond, which means that your almost immediately set to fail since there are too many asteroids and no way to dodge them. I also kept getting random deaths. with a little shine and polish the idea could be clever, especially as a sidescroller if removing the hitbox from the rainbow seems too difficult to program. But as it is its unplayable, good attempt though!
This is actually really, really bad and shouldn't be on the Under Judgment page. It's an average first attempt at a game, but it shouldn't really be uploaded here unless you just wanted feedback. The music is really loud, the score doesn't work at all, the white bars at the top and bottom of the screen need to go away, and it's impossible to play since the entire rainbow trail behind Nyan Cat counts as its hitbox, so if anything touches it, it's instance game over. There's a lot wrong with this that could have been polished up a little more before uploading it here.
This. Is. AMAZING!
no tutorial or menu, too easy and repetitive, goes nowhere