Hey man, I really liked this entry .
I've listened to all the compo tracks many times this past week, so I'm pretty familiar with this mix by now.
The opening/closing riffs are cool, and I like how you made them kind of off beat, but the instrument itself sounds really synthetic. Maybe it's just me, but I think a more natural instrument would sound better there.
Also, I think the drums could use some work. Since it sounds like you're using acoustic samples, you might want to try making them sound a little bit less programmed. Some more variation would be nice too; repetition is fine, but after a while they get kind of boring. I'd really like to see them get changed up at 0:25, 0:55...basically whenever a new riff starts or instrument comes in. You don't have to go crazy, but little changes in the beat would be nice.
Overall it's a very enjoyable listen though!