Hey man doesn't sound bad at all, considering you mixed and mastered the thing in 24 hours that is insanity! Overall I'd like the drums to be a more upfront and hit a harder, it just sounds like they need a little bit more space in the mix as well.
The guitar tone I actually really like for this sort of stuff, I think the reason someone said it sounds a little hollow is that there is quite a big gap in the low mids I think between 100-200Hz that I wish the bass was filling up it would make this track sound massive. Northlane's album has been a great reference for me in this regard, the bass sits in a really cool spot between the kick and guitars.
Ah and I just noticed, some of the edits are a little bit dodgy, it kind of sounds like you've cut the bass and guitar to the attack of the kick drum in the breakdowns and have taken off the pick attack. Considering you only had two weeks to track and album which is just insanity in my book and then 24 hours to mix I can forgive some of it being a bit loose haha.
But dude if this is your first job, that is absolutely mental. Probably the best sounding first job I've heard!