Part 23

Return to Stark's office. Explore for stat upgrades, a sketchbook, and access to the trivia game, game stats, and simulator missions.

Talk to Nick Fury to begin the final mission at Castle Doom.

Advance through the first area of Castle Doom; a stone staircase will appear. Climb it.

Proceed along the balcony to a stone bridge. Cross it and enter the next room.

In the room with the Y-shaped walkway, destroy the knight statues with ranged attacks to reveal treasure chests containing a Daredevil action figure and a skill point.

Continue to the Hall of Many Doors. Ignore the north and south doors. Find the prompt to 'Enter Door' on the left side and press USE.

Go down the stairs in the next room and jump into the pit.

In the large room with the Doom statue, locate a sketchbook to your left. Note the inaccessible SAP icon and stat upgrades around the statue.

Examine the Doom statue by standing near its base and pressing USE to update objectives.

Enter Doom's Lair through the door on the right.

In the first library, jump into the center to access Energy and Health Stations. A flyer is needed to return to the upper level.

Go past the library to a second library. At the second door on the left, enter the side room and USE the large bookcase to reveal a secret room with a weapon cache containing a Black Panther action figure.

Return to the library and enter the first room on the right to find a skill point.

USE the large bookcase in the far corner of the library to open a secret passage.

Work through the following rooms, picking up the sketchbook in the second room. You will pass an inaccessible SAP.

Reach a large room and fight Dark Captain America and Dark Colossus. Use ranged energy attacks on Cap and elemental attacks on Colossus. Utilize extreme powers if available.

After defeating both dark heroes, head up the stairs and pick up Doom's gauntlets to enter Doom's Dimension.

Go up the stairs and enter the Stairwell, a side-scrolling area. Fight your way up.

At the top, pass the door to the Dimensional Cavern and use the SAP to save your game.

Enter the Dimensional Cavern and fight Dark Psylocke. Cyclops will leave.

If you fall off the platform, fight Dark Cyclops at the bottom of the platform.

Defeat both Dark Psylocke and Dark Cyclops. Cyclops's optic beam has a stunning effect.

Advance to the Hall of Arms, which contains Doom's armor. Pick up the sketchbook to your left.

Pick up Doom's armor and go through the door behind it to enter Doom's Lab.

Fight your way across the large room and up the center stairs.

Take a left, go across the hall, and pick up the last sketchbook from the side room.

Follow the hall to another side room and pick up the Ultimate Nullifier.

Go back to the center door and proceed down the hall with three fluctuating beam barriers. Dodge the beams.

Open the door at the far end of the hall.

Save your progress at the SAP.

Cross the rolling path. If you have one non-flying hero, escort them across. If you have more than one, you may need to experiment with getting them across.