Awesome.

Sucked me in for an hour from start to finish. I'm just trying to get all the achievements now! Good range of enemies, although some (the one that spawns minions) last a bit too long and the rounds go on and on.

Thanks!

Needs improvement

As said below, you need to adjust the levels. If you're finding one instrument dominating the other then start adjust the EQ levels, make sure each part occupies it's own "sonic space" - the kick should be low frequency, etc.

Hope this helps. I'd like to point out a few parts of the synth line don't sit right with me. Most of it does, apart from at the end of some of the phrases where you go down through semi-tones on the last three notes (I think it might be E-D#-D,) it sounds a bit cheesy.