Vocals really suit it.... but not the pitch shifted parts, which changed it from cool and threatening into something more suited to an episode of Power Rangers. Being less than a genius myself with lyrics I won't comment too much but I will say there are too many fucks so that the swearing impact is lessened. All underlining is no underlining. Because the pitch-shifted parts are playing in the same range as the bass drum and bass instruments they're clashing quite a bit and need some EQ carving to clear it up. Probably a decision needs to be made what has priority in those parts.
Now, despite what I've written above I rather liked this. Its good a mean moody feel I enjoyed and its nice to hear someone doing vocals on here. The piano sounded good and fitted well.
Good work, doing vocals is always scary when you put it out there