It's actually pretty good!
Your screaming is pretty good, considering how bad most people are, for that alone I'll give you 4 stars. The songwriting is wonderful. Very good death metal guitar parts, and awesome drums (although its not hard to make double-bass rhythms and blast beats with midi drums), but I'm impressed. 3 more stars. 2 more star for the hilarious lyrics.
Then there's the one thing that drags your score down, and it's pretty obvious. You need a better guitar synth. It doesn't sound ear-bleedingly horrible most of the time, but it really ruins the song. I take off 2 stars.
Overall its good, now get a band and play it on real instruments.