To unlock Hard difficulty and Skrull Arena complete the game on Normal difficulty.
Unlock the following bonuses by obtaining the corresponding amount of tokens:
BONUS – TOKENS
Comic Covers I – 4 tokens
Comic Covers II – Get 4 tokens
Concept Art – 4 tokens
Fantastic Four (1990’s) – 12 tokens
Fantastic Four (21st Century) – 12 tokens
Ultimate Costumes – 12 tokens
Filling the cosmic energy bar:
At any time, do a taunt. The taunt may seem to do nothing, but it is actually filling a small part of your cosmic energy bar. The amount filled by each taunt varies. Note: It is recommended that this is done when there are no enemies around.