While waiting for any of Spider-Man's missions to load, hold Select to turn his red costume into Venom's black costume.
Defeating Electro
When you fight Electro, about half way through the game, hit him with your tendril. When he turns blue, use the stylus to throw blue mail boxes and the car. The car will respawn if you destroy it. If he gains health, use the tendril when he is red to take out the street lights. The lights will flicker after you hit them, but if they are not out he can use them to regain health.
Play as Carnage
Get a 80% game completion to unlock Carnage in Multiplayer mode.
Play as Symbiote Spider-Man
Get a 100% game completion to unlock Symbiote Spider-Man (black costume) in Multiplayer mode.
Venoms Death
This code only works if theres a ceiling above venom,when your he is dying(when hes on his knees and flops over)touch the stylus on venom and he will zip to the ceiling. He will be alive and youll be ale to play with an empty life bar. However,if you get damaged though youll die but you could could do that as long as you have a cieling over venoms head. Also feed on someone to keep you from dying if you do that trick.