Wow, rock on! Excellent jam. Well played instruments! Although I'd suggest that maybe you could tone the volume down just a hair--for the drums deserve to be heard a bit better!
What language are you singing in? I almost thought you were singing Japanese and then thought "All right, I love J-Rock!" But only for a second. Then I thought, "Wait a minute--no, it isn't Japanese... The dialect sounds a bit different." I'm just curious on that. It'd be nice to hear the word English, but then that's okay! I like it a lot just the way this is! The recording quality sounds pretty good too. Singing was in good key, and not off pitch.
More voices? Hmmm... Maybe you could try some harmony in the verses. That's all I can think of. Give it a try. I didn't find much problems while giving this song a listen, only that very minor one about the guitar almost drowning out the drums. :)