Started making/remixing moosic, need some feedback

So recently I started to take music remixing/creation/edting a bit more seriously. I had FLStudio on my iPad and I decided to remake the Doom intro theme song since its my most favoured theme song from any game. Originally I created the guitar and drum parts for it, but then I thought it'd be a good idea playing around with the instruments to see which gave it a sort of heavy/electro feel. I then created the extra parts such as the other electro pads and a few more adjustments. So what do you guys think? Is it shit or is it decent? Any music pro's maybe give me some tips on improving it?

video