Boss theme thingy Options

[Godspeed]

Well, although being a musician for years I've never tried making music with a computer software for serious or themes for videogames since it's something beyond my experience and music genre. That doesn't mean tho that I don't enjoy fighting a boss while an awesome theme's giving me the chills!
So, after a couple of months playing around with some MIDI composing softwares (making some drumbeats for drum programming purposes cuz ultra fast death metal drummers are so hard to find) I decided to make a quick theme and post it here. The sample below is just a track I've made half an hour ago having that good old "Still more fighting" style in my head playing on repeat. After composing that stuff I've converted it to mp3 format for no particular reason.
Even if it's just an idea with some major tone mistakes, I would like some feedback guys, just to help me decide if this baby deserves some more work and a decent structure!

Thanks in advance!