ok... 1st boss- just move side to side avoiding the bombs (the minigun doesn't do all that much damage)
-if you see any red buttons anywhere on any level shoot or hit it.
-to jump up to high places, jump sort of backwards (so you dont flip) then flip.
-before the reanimation chamber dont go in, keep on killing people to go to the next chamber up (bean chamber)
-only use pipe on beans for an easy 500 melee kills (for sword)
-on room after zombies or beans just stand in the doorway holding s and a and melee like crazy
-elevator levels- stand in the middle of the elevator meleeing upwards.
most of these ideas were by other people btw xP
im on the stage after the beans (or zombies) and ive killed like millions and the door wont open, once i actually got the door open but then got 1-shotted in the back of the head -.- maybe just spamming pipe while backflipping against the wall would work?