This build is for people who are too lazy to deal with ammo.

The cards: Yami Knife, Shot Faster A, Power! A, and Plz more.

How to play: Hold left click and do not stop. thanks to shot faster A it'll attack very very fast and thanks to power! A you'll be able to plow through enemies easily. If you know the levels it should be quite easy to get through them.

The bosses: the bosses take some strategy.
For the first one, it goes down fast so keep attacking, right click when you can and if you see your health go near half kill some enemies to regen. thanks for Plz more! you wont have to kill many to get to full.
For the second, stand withing hitting distance and jump up and down. Youll hit the boss in the air and on the ground youll kill the re-spawning enemies. if the enemies get stuck in a position where you arent hitting them just move forward and back as you jump. itll take a little time but itll die.
For the final: this is the hardest. Keep moving, strafing, whatever. Circle strafe and try to kill the enemies near the boss. If you see you health get near half, go out and kill some enemies. Why near half? because any lower makes you vulnerable to the boss's projectiles. as you run out youll probably run straight which makes you get hit and die. This killed a few IV-Dizzy runs for me.

this help? I hope. GLHF