I'm a terrible drummer, so my advice isn't worth a hill of beans. But still...Try adding some ghost notes on the snare to give a little more human feel. And vary the velocity of some of those notes, like the hihats that don't occur on a 2 or 4 beat. Crash cymbals in particular suffer from max-velocity hits. I always back off on the crash velocity or else they sound like some robot caveman trying to destroy a perfectly good piece of brass. Depending on which sampler you're using, you can always bring up the overhead volume in the mix, or bring up the volume of that cymbal in particular. Usually I find that I don't need it.
Take an evening and try to tap out that same rhythm on an imaginary drum set. Pay attention to how hard you hit certain notes. See if you can start to see patterns in how the accents fall (mainly on 2 and 4 beats). Lighten up on the notes that don't occur on 2 or 4 in a song that's in 4/4 time.
Getting a human feel while step-editing in a piano roll is really tough. It's as much an art as a science, and I'm apparently neither artist nor scientist when it comes to this. Every time I try to dink around with velocities and accents, I end up with something totally inhuman. I play drums at a kindergarten level, but I still have better luck with an e-kit than a MIDI keyboard or step editing in piano roll.
Nice heavy guitar tones though, and I like the organ. Cool solo at the end as well. And your drum samples sound good to me. See how it sounds to you if you back off the velocity on some of the kit pieces. Sometimes those not-quite-100-percent hits sound more convincing than the full-on 100% hits.
There was a funky clean-ish guitar part that I thought sounded too dry.