Alright, without going overboard:
The 'clean fills' being played need to be sorted out. They're too much just like plunking on random strings with no conviction whatsoever.
The bass guitar is only playing the root note of each riff. Fair enough if he's a new bass player and doesn't know any better, but it leaves the dynamics of the song very flat.
What's worse, the rhythm guitar and drummer are playing the same rhythm. So that means that you have:
drums = rhythm guitar = bass guitar = NO sonic variety!
The screaming isn't actually all that bad for the genre. If you don't blow your vocal chords out before the show, you'll be fine. A bit of distortion doesn't hurt, either.
----
Regarding production:
If you can only get 3 tracks of audio before needing to bounce, you'll need a new computer before you can get too much into it, and you certainly won't be able to run Ableton Live. But, when the time comes, or if you want to be creative:
- Your vocals need heavy compression to smooth out the dynamics. Also, you are clipping, which means that the limiter/maximizer in Audacity isn't doing its job transparently. You'll need something less distort-y
- The bass guitar needs compression as well. Right now its attack doesn't pop enough. Maybe a different technique wouldn't hurt, either-- use a pick instead of a finger, or a finger-snap instead of a finger-walk.
- Always mix everything based around the rhythm section first. Right now the whole mix falls apart because the drums aren't sitting right in the mix. It might be hard to get them to sit right with their current rather 'thin' sound, but they do need a bit more presence.
That's about it without going nutzo with advice.
Greg