The feats and your progress can be tracked via the pause menu. Complete the following feats:
Feat: He is perfect the way he is
Description: Collect 4 Herbie Upgrades
Reward: Challenge Map - Lost in the Negative Zone
The first part can be found on episode 4. You will need to use Nova to activate a vortex and suck some bombs to a control panel to get past the red laser wall. Once you do you will see the glowing blue object in the background.
The second part can be found in the headquarters after episode 4. It is by the control panel in the reactor room. This is the room that also has a little robot floating around in it.
The third one can be found by replaying episode 7, “City of Doom”. At the very beginning you have to fight a wave of enemies. In the second room, before going outside there is a zipper on the wall. Switch to Thor to open it and collect the part.
The fourth one can be found in episode 10. Defeat the dark Nightmare and Hercules and then before leaving the room switch to a strength character. Now go jump onto the ledge by the monitor in the back left corner of the room and then jump onto the top of the monitor itself. Break the wall and enter the hole for a secret room. In the back right corner, up on a ledge is the final part.
Feat: Time stone fragments
Description: Collect 100 time stone fragments
Reward: Classic costume
These fragments are found in episodes 7, 8 and 10. You get fragments by killing enemies, destroying objects and finding secret areas. You can replay the levels via Free Play until you get the required amount. While in Free play, you will be able to freely swap to any character type you need by holding down the button and then pressing up or down until you get to whoever you want. You can check your progress in the fragment display room found in your headquarters.
Feat: Clearly forceful
Description: Complete all previous feats.
Reward: Achievement unlocks.
This unlocks automatically when you complete the other 2 feats.