I believe that this is technically a synth rock, it really doesn't have that dubstep vibe (solid sub bass and half beat feel)
Musically it is good, something is constantly happening, so it doesn't get boring at any point
mixing is OK as well, but the instruments could be "wider", you know ,some layering, compression, reverb, don't know what are the possibities of garage band though
2:03 - there was some note off the scale, watch out for that
0:38- I dont like this snare much, the other is cool
Otherwise it's quite a decent tune, I would imagine it as a soundtrack of some mobile game maybe
btw why genocide? Under such a title, I imagine something darker, sinister.. this sounds quite encouraging actually
and good luck with future production :)