omg how is the final boss impossible? I beat it in like 45 seconds. just get a bunch of lasers in the back, fully upgrade the ultragun (except the health, dont ever upgrade the health) fully upgrade your drones, and then aim for the boss' main ship. GOD its not that hard.
When psycho goldfish laughs, hit him with a bomb, when mindchamber shoots the missiles, get them to hit him or one of the animators, when stamper and jeff come out, let one guy go up in the air, and kill the other while avoiding the pink blobs. For wadolf, run around the zombies, get him to shoot the laser beam, then run behind him and throw a bomb.
For wadolf just wait till he summons zombies, attack him, and run down/up. The zombies will be hit by the shoopdawoop beam, but you still have a big chance of being hit. I hate that thing
oh ya, on level 8, if you don't need money, or you just can't beat it, then kill everything but one eye tower and dodge the bullet the rest of the time.