Sounds like old-school thrash, reminds me a bit of Metal Church and Slammer actually. Since it is so repetitive, the riffs all have the same basic structure, it gets boring without a proper arrangement (and it might still be boring with drums/bass/vocals, who knows). And the part at about 4:10 we've heard at least 10 times too many already. Unless there's a killer guitar solo planned there I'd leave that part out no matter how much you like the riff.
"If money is the root of all evil, I'd like to be a bad, bad man."

- Huey Lewis & the News