Hey Clayton! I listened through your soundtrack and the mixing/composition sounds very well done. I would say bring the rhythm guitars up more, since they tend to act as a cushion. You have a lot of interesting parts and I can hardly hear them. A few of the guitar instrumentals that I am used to hearing tend to have loud rhythm sections (although I would totally opt for the leads to be a bit louder).
Did you use references while mixing? What type of sound were you going for?
A few tracks that come to mind (instrumentals);
http://music.basickrecords.com/album/all-roads-lead-here (rhythm heavy, but it's djent)
(rhythm heavy, BUT AGAIN, it's djent)
With panning, too, aside from leads (which can be compared to vocal leads), most rhythm guitars, or lead motives that act as a rhythm, are panned to the side, and give the bass the middle (which you've done), allowing the drums to have the center with spread in the back.
Most of your guitars are centered (and feel distant). Almost in the same vein as the bass.
Did you record this live, with a band? Or did you record each part individually via amp? Or DI? Mixture of? Are you looking for a close sound, similar to:
That's what I meant by having a nice cushion with the rhythms. Even though there are leads playing, you feel snug between them. Then the bass comes in, and then boom, plenty of headspace for a lead line.
Another indie band with a nice open, instrumental sound:
https://www.youtube.com/watch?v=KAp96n9iL_gRhythms on either sound, bass centered, with drums also in the back spread throughout.
Another example:
https://www.youtube.com/watch?v=Hp5ro-Gm-3g&index=4&list=PLOWQezuXRmTFeUWsD4eeE4KWcLN6mNtn6&nohtml5=FalseHaha, hopefully you get the gist.
Aside from spacing and instrument placement, the mixing aspect (editing frequencies and getting the instruments to fit in the headspace) are really good!
Oh, another way to get your guitars nice and full, is to stack recordings. Record the line meant for the left ear about 2 or 3 times (or maybe 4 or 5), and do the same for the other side. Gives a bigger, fuller sound and is REALLY common.
Hopefully John Fio will chime in on this too, because he wrote a guitar heavy game soundtrack a while ago:
https://soundcloud.com/audiosprite/04-heaven?in=audiosprite/sets/epanalepsisIs the game out already? I enjoyed listening through, by the way!