Marvel Super Hero Squad: The Infinity Gauntlet

Collect all the Power Stones in Level 1 and Level 1-2 (the rocket level). Level 1-2 required a couple of playthroughs for me to get all of them, as it is a scrolling level, so you don't have time to go backwards. Whatever you don't get in these levels (should be less than 20) you can pick up in Levels 8 and 10.