If you defeat the enemies out of order, the boss in the vacant warehouse will not appear, and you can't get into the high school. You have to beat Blade in sherman park directly after you are told he is waiting there. I still haven't found any way to get back on track if you don't go in order.
IIRC, he's still there long after you're told he's waiting there, so if you go back to Sherman Park, you should be able to cream him. Anyhow, if you're unsure which bosses you may have missed, check out the TAS on tasvideos.org. They beat only the necessary bosses, and the run is hilarious!