I really dig the way the guitar sounds on this track. Has lots of attitude going on, which is good for battle/boss music. I think it took a little long for a melody to come in (47 seconds, I think?). The first chunk of the track is dominated by a low range of frequencies, which is alleviated somewhat by that funky keyboard that comes in later on. My 2 issues with the keyboard are: 1) the part it plays (funky, jazzy, kinda Steely Dan-esque) doesn't really jive well with the attitude of the guitar, and 2) at some point, the keyboard and guitar seem to be a little bit out of tune with each other. I don't know for sure; for all I know, it could be a psychological thing.
I would recommend a high frequency instrument like a high string or synth or something like that (or heck, even that same guitar but played on way higher frets) to play a badass melody on top. I think that would really make the track come together.
Oh, forgot to mention. I LOVED the filter sweep/transition things you did throughout the track. I think they happened like once at the end of every 4 bars or so? It was really effective. Also, I dig how crisp the drums sound.