I felt like this piece never really got momentum started, and I think a big part of that was the relative absence of drums through most of it. It's really important that a piece as energetic as this has some sort of unpitched percussion driving it. I guess this is also because the cool hi-hat pattern that started at 0:37 led me to expect that it was going to build into a dramatically layered drum track, when it actually just faded away.
The lack of drums also made the textures seem kind of thin at points. The section from 1:24 through 1:48 was very little more than a dirty lead playing a single note and a couple of simple drum sounds, and although you made some good rhythmic patterns with them, I don't think that combination works on its own.
The arpeggiations that started coming in at 2:13, I felt, didn't fit in well with the harmonic structure of the piece. I'm no music theorist, but it felt like the way they changed key rapidly contrasted poorly with the droning quality of the rest of the piece.
I thought the intro went on a little long as well. If you had added in some more sounds and perhaps a more complex melody or harmony, it would have made for good ambiance, but as it is it wasn't particularly interesting over the course of a minute. I thought the loud bass pulse at the very beginning was going to build into something bigger, and when it just went away I was somewhat disappointed.
The production and choice of sounds on this piece was quite good. The lead was powerful and dirty, and I would have liked to have heard it mixed in with other sounds. The percussion that you did use fit really well with the melodic sounds, and the piano provided a good contrast with the roughness of other parts. I didn't like the choir-like samples in the beginning and end, but that's purely a matter of personal taste. The eerie screeches that appeared around 2:05 gave the piece a great atmosphere that I thought was lacking from the rest of it.
Overall, I think you're doing well in coming up with cool sonic ideas, but you need to work a bit harder in structuring and composing them, and think about how the intensity of the piece rises and falls.