At the beginning of the mission turn right, approaching to the green box. Destroy it and manipulate violet bricks with telekinetic abilities (e.g. Jean Grey's) to create a proper connection for the cables.
Choose Magneto and turn left, approaching to the metal box. Open it to unlock some black cosmic bricks. Manipulate them using Galactus powers to build a toy. Drive it for a while and you will receive a minikit.
Choose any big character and head to the upper-right corner of the location. Yank two green handles and then extinguish a fire using Storm or Iceman. After that fly to the top of the shaft using flying hero to catch a minikit.
In the same location three barrel racks are hidden (one on the left, two on the right) - destroy them to obtain a minikit.
Go to the next stage and fly to the podium (located right at the beginning) and choose a character with claws. Use them to turn the claw switch on, so you can jump down and dig out a minikit from the sand pile.
Head left, looking for the blue metal wall. Destroy it using Magneto and construct a throne from the debris. Then turn left and freeze a pool of water using Iceman special abilities.
In the same place choose Spider-Man and use spider sense to uncover a passage to the upper floor. A minikit is hidden at the end of it.
Fly to the higher level and stand at the edge of the platform. Use Jean Grey to take control over the Magneto Acolyte and jump up, so you can catch a minikit.
On the right side of the same location search for the iron bars and pass through them as Mr. Fantastic.
The last minikit can be obtained during the boss fight. Switch into Magneto and open three metal cages using your magnetic skills (they are located on the left, on the right and at the bottom of the arena).