All the tracks sound pretty cool, but having not heard the original artists, I can't tell how much of it is your own, and how much of the coolness rides on the original coolness coattails. But anyway, I doubt that you did too much of this, so excellent job.
Are the vocals on track 3 supposed to be so detuned? It sounds a little odd to me. And either way, track 3 seems a little weak to me - kind of too sparse in comparison to the previous two tracks (which are awesome.)
The bass on track 4 didn't seem to blend very well with the other track. Maybe it was too much panned out to the stereo while the other track was too much in the center or something? Either way, it sounded a little too much like two separate songs playing at the same time sometimes, rather than just one song. Around the 2 minute mark, other stuff comes and fills it in, so this is much less noticeable. But before that, the bass seemed too removed to be part of the same song. Past the halfway mark, the song is good, though. (Although repetitive, but what more can you expect with this genre?)
Once again, on the last track, it was fine until the pounding bass came in. Then, the vocals felt tacked on, like they weren't anywhere near the same EQ range of the other song, or something. Whatever the reason, I just felt that they didn't blend very well. Maybe they just needed to be louder. It got better, though. The second time they came in around 3:40 they seemed to blend better, perhaps because of the other vocals to fill in the space? (I really don't know shit about what I'm talking, I'm just telling you what I heard and thought when I listened to it.)
Out of curiosity, what program(s) do you use? If you don't mind divulging this sacred information, of course.