The feats and your progress can be tracked via the pause menu. Complete the following feats:
Feat: The Offices of Walters, Lee and Awesome!
Description: Collect 4 misplaced legal documents.
Reward: Challenge Map - Whack an Imp
The first document can be found in episode 3. While going through the level you will come to a stone that you can pull out with Hulk. Do so and a platform will lower in the back corner. Your partner will jump on it and you need to push the stone back where you found it to raise it again. Swap to the other character and leap onto the back ledge to grab the glowing red item.
The second one can be found in the headquarters after episode 4. From the main room, take the right exit and you will be in a hallway with 3 doors. Take the door on the right into a room that looks like sleeping quarters. The brief is just off to the left.
The third one is found by replaying episode 7. After the freefall section, you will shortly come to a part where you need to use Spider-man to web a hole and use Reptil to cut a rope that will destroy a cannon. After this you will be on the side of a blue building and 2 Doombots will be shooting you from a floating platform. Destroy the Doombots and the platform will lower allowing you to jump onto it. From there you will go to a hanging platform and finally back to the side of the building. As soon as you land on the other side, you will see a glowing portion of the back wall. Use a strength character to break it down and collect your brief.
The fourth one is found while replaying episode 8. At the very beginning, wipe out the Skrulls, hack the terminal and shoot the snipers and force field with the cannon. Before moving on, switch to a strength character and break the boulder on the left. The brief will be right behind it.
Feat: Jaw of Death
Description: Defeat 100 enemies with She Hulk’s scream attack
Reward: Savage world costume
To do a scream just hold down the button. This is cumulative and counts throughout story mode, free play and Challenge mode.
Feat: Law and Order
Description: Complete all previous feats.
Reward: Achievement unlocks.
This unlocks automatically when you complete the other 2 feats.