Galactic Jump is a side scrolling space themed game where the objective is for you to survive as long as you can following the "rainbow" trail, available on Windows Phone 7
Travel along the worm hole (which looks suspiciously similar to a space rainbow) without hitting its sides for as long as possible with your space ship.
WP7 Marketplace Page
Tap - fly up
Flick - fly down
Oct 2011: Fixed some bugs, updated controls for user friendliness, adjusted the level generation and difficulty increases and added support for leaderboards.