Whahaha
Well, I loved Portal, so I know exactly what the origin of this track is. It's too bad that you didn't fit the right dialogue of GlaDOS fitting to the song. The ending is great, but I didn't like the middle part, she has so much excellent speech you can put there, but IMO you shouldn't have put the bossfight dialogue in this song. Also, I think you should give the background music a bit more attention than this. I didn't feel any bass, nor heard it.However, I have excellent speakers, so I think there is just no bass. The melody got fairly annoying however, you could have made the middle part melody somewhat more interesting.
The ending and the beginning where great though, and the music fit great to the speech there :) Good job dude, only just shine it up a bit.
Alex\/