Unlockable Costumes:
Unlock the following costumes by performing the corresponding tasks. Note: Select costumes from the profile screen:

Coipel Thor (costume designed by Oliver Coipel) – Vanaheim (The Arrival); after charging the first door and going through it stay on the overhang and walk behind the tower with the door
Destroyer Thor (Destroyer wearing Thor’s cape and holding Mjolnir) – Complete the game at any difficulty (tested on normal)
Kirby Thor (costume designed by Jack Kirby) – Niflheim (The Approach); after throwing the statue head, it’s to the right of one of the giant stairs
Ultimate Thor (Ultimate Avengers costume) – Midgard (Burning Town); in the same area where you saved the trapped civilians from fire outside the police station