Unlock the following characters by pressing the corresponding sequences of buttons while on the Helicarrier:

CHARACTER - HOW TO UNLOCK
New Goblin - LEFT, DOWN, RIGHT(2), DOWN, LEFT.
Sandman - RIGHT(3), UP, DOWN, LEFT.
Venom - LEFT(2), RIGHT, UP, DOWN(2).

To receive 5,000 upgrade points, while you are standing on the Helicarrier press Up(2), Down(2), Left, Right.

Unlock the following characters by performing the corresponding tasks:

CHARACTER - HOW TO UNLOCK
Black Cat - Beat Toyko level 1.
Blade - Beat Transylvania level 2.
Doc Ock - Defeat him in Tokyo level 2.
Green goblin - Defeat him in Tokyo level 4.
Iron Fist - Beat Tangaroa island Level 3.
Lizard - Beat Cairo level 2.
New Goblin - Beat the game.
Rhino - Defeat him in Tangaroa Island level 4.
Sandman - Defeat him in Cairo level 4.
Scorpion - Defeat him in Tangaroa island level 2.
Venom - Defeat him in Transylvania level 4.

While fighting the Green Goblin, he will throw pumpkin grenades at you. While he is throwing his grenades, change characters. The grenades will explode in mid-air.