I also STRONGLY advise you to try zooming out to max when playing.
You must destroy all 99 of those air-hovering enemies which will open the way to the exit. It only takes a one-hit wonder to destroy each of them, fortunately.
To be honest, it may be a little crude and underdeveloped, but the environmental feedback looked satisfying when I play-tested it, don't let that fool you, however...
RS0002