I like Monster

The composition and structure of this song is actually very good, man. What makes this song sound unpleasant and "really bad" as MadrugaKing stated is the mastering. Bad mastering can ruin a good song, and make a bad song sound decent. Good mastering is arguably equally important to composition. You're still using Reason 4, right?

First of all, make sure NONE of the channels are maxing out (that means going into the red). Yellow is for the loudest of your instruments, but never red. Furthermore, think about what each channel represents. Which one is the lead? This should be the most dominant. What about drums/rhythm? The should be loud as well, as it's keeping tempo for the rest of the instruments. (I realize that they aren't really keeping the tempo, because it's electronic and it keeps the tempo by itself, but you have to think as if you were composing something to actually be performed by real instruments.)

As for drums, when you look at your Redrum machine, look at the individual audio levels for each sample; those require close attention as well.

uh...

sorry dude, this song is really bad.. it hurts my ears.