Very Good
this is pretty sweet, but some of the sounds and harmonies could work better together. The backing filtered synths don't sound to great with keyboards upfront, you might want to select a different sound. The harmonization seems a bit awkard around the transitioning at 00:13, it might not be a fault in the actual composition but the synths classhing. its not too bad in the second half, so no real beefs here.
One aspect of this track I love are the kickass, fast paced battle suitable melodies. The piano riff in the intro is sweeet, you establish it with some nice melody, use the "galloping" triplets, and do a great job of using the same theme and harmonizing. I really dig how you have the super fast arpeggios, with a nice guitar (or whatever) chord progression to back it up. the ending is abrupt, you might want to slow it down before it ends, or atleast end on an extended chord/note. I would definetly love to see some phrasing done here, and here the same portion that you used in the intro, but that's not necessary for a boss battle piece.
Mastering work...could use some polishing. I mean it's nice and full, takes up the stereo, but the panning, is weird? I like how the piano flies around my speakers, but it kinda takes up too much space from the other sounds. Like the main synth you used, I can't hear it all during certain times. And the drums could be a tad louder, and the closed hi-hat should be panned to the right a bit.
But who cares? This is pretty sweet man.