there is no cheat for all characters.
onlock peggle code
you have to beat arcade mode
You have to buy the full game to have all the characters.
well if u play to a point, ull unlock some people
you can unlock the following characters on marvel ultimate alliance Blade,Black Pather,Dr.Strange,Nick Fury,Silver Surfer,Daredevil,Ghost Rider and on the gold edition or the xbox 360 ''hero pack'' and ''villain pack'' you can also unlock Dr.Doom,Sabertooth,Venom,Magneto,Hulk,Cyclops,Hawkeye and Nightcrawler.
Yes, there is a cheat code to unlock the deappool in Lego marvel.
many, check out www.marvel.com for more info on marvel characters.