work on getting supplies/extra time first! learn where all the extra time bounuses are.. i completed all stages with all characters with 5 stars
village---get all time bounes, then when you have a big crowd run to the building that has the red barral, climb up the ladder, and get the 30 bounes/kill and stay up there until they stop coming.
mining- same thing with time bounuses, when i played there really wasent a great spot for hiding-least favorite level.
Water level/Dock- same thing with bounuses, the first chainsaw guy you hear, run up to highest BUILDING (not the tower) and kill lhim from there. youll face i think two of these guys, the second one, just kill in the area you find him in.
Castle- imo the hardest, easy with some characters but hard with others.. Dont spend TOO much time in the begining running around, this level is more of a direct path you take instead of just runnning around.. your endpoint should be a the very top on the far left where you find the BIG door and bunch of crossbowmen. youll also find the the second/third blind guy here. after, just stay in this area and rack up combos
basically just rack up combos, getting time bounus is one of the most important things, make use of all your inventory.