Help me improve my recordings:

I just listened quickly, but I'm wondering if you have a bass guitar going on...guitars sound pretty decent to me. bass drum might be a little low in the mix.
 
The bass is pitch shifted guitar, it's not very good.

I recorded 5 guitar tracks, two with a treadplate patch, two with a diamondplate patch, and the middle one with a big bottom patch.

The treadplates are panned 100 to either side, the diamondplates are panned 70 to each side, and the big bottom's in the middle.
 
Is the middle guitar track always playing or only for leads ?

If this is a rythm track that is always playing you should remove it, and bring up the bass (if i were you i would write the bass tab with a software like guitar pro, and then export the wav and EQ it to make it sound decent or use the tab in a bass software like hardcore bass or whatever) panned in the middle and try to make it sound big ( "putting in a nice growly, crunchy bass would really fill up the mix better" as grywolf already said)

+ more bass drum

then it will sound great.

To me the guitar tracks sound great for a mix right now (but remove the one in the middle)