Lot's of respect !
Dude, believe it or not, but since I discovered your stuff I picked up my guitar again. Your stuff is damn inspiring !
As for this song, I'd say that the riff at 3:55 is probably the best "Dude going berserk and destroying everything on his path with a sledgehammer" riff ever ! :D
Concerning your music, I love this raw kinda sound, it makes the whole thing "real". If it was to proper it wouldn't be the same. Guitar sound: perfect. Drums sound: could use some better mixing (especially the snare which is often too loud in my opinion). Vocals: don't you ever try ^^, instrumental is so much better for this type of metal. Bass: could bring some serious depth to some parts (if there was any).
Overall: You kick some serious zombie ass ! :D and thanks for the inspiration !