Nice feel to it man. Bass seems a little hollow unless you untended it to be that way... oh nervermind! Snare seems a little weak as well, but when that bass dropped it sounded a lot better. Though, by itself I'd adjust it a bit. The drop out seemed a little quick, add an effect in there to signify a change coming.... Just my 2 cents
Keep it up man!
To sort out the low end you should should just put a pure sine/tri wave playing the same riffs you have now and then high pass the actual bass sounds at 100hz. That's how I do it anyway. Then i tend to mix in a square high passed at 100 and low passed at whatever sounds good with my toher bass to give a fat mid range. I could jsut be a full retard though.