In boogie nights you will come to the rooms where you have to decapitate the dancing zombies. Just stand near the exit. The heads won't follow you there. From that spot you can snipe them easy with your funky gun.
To get almost infinite health go into happiness and go into the good the bad and the elderly. Then go find a granny whip it 3 times until it's dead. Then shoot the front part of it (the white part) then Jimmy will keep shooting it with his machine gun killing the granny a numerous amount of times giving you lots of atomic healths.
For infinite lives in the happiness stage first you have to get the 12 golden udders in memory to get to happiness. When you do get there there will be a Snot over to the left and he will give you a fart power drink. Go to where the extra life is and get it. After that go into the room next to you and go back out - now go back to snot to get the power and do the same thing over and over until you want to stop.
To play as Earthworm Kim, you must get all 1000 marbles (as smart as a smart super hero) and have all of the uders. Then go into fear and into the mansion the gate that's always been closed will be opened when you go near by it. If this does not work do the same as above but beet Earthworm Kim.