Objective 1: Clear the Purple Gas
At the start, beat down the foes that are waiting for you. Take care to use ground finishers while in the fight and you can also complete the combat challenge early on. After taking care of the baddies, head to the left.
Combat Challenge: Finishers
Take care not to get too close to the flower and pass by it. On the far left side of the stage, you find the first Batman prop. Smash it!
Batman Smash Challenge: 1 / 3
Go back to the flower and use a character with lasers to destroy the gold LEGO panels on each side of the plant. After you destroy it, you have the chance to destroy the nearby pump. Look for the electricity discharging from it.
Head to the far right side of the stage, past the path blocked by purple gas. In a small nook, you find another pump. As with the other one, the pump is putting off a good amount of electricity, so it’s hard to miss. Destroy the pump to cut off the flow of purple gas, allowing you to pass.
Objective 2: Shatter the Glass
Head north up the stairs. Fight off the bad guys and continue past the stairs and to the right. Tucked away you find four mushrooms. Jumping on these fungi causes musical notes to play. To unlock their secret, jump on them in sequence. Starting from the top, jump from mushroom to mushroom in a clockwise pattern to play the melody. This melody causes a nearby flower to open and reveal The Joker Card.
The Joker Card
Head up the stairs and smash the Batman prop to your left of the stairs. The final Batman prop is on the right side of the area, across from the LEGO glass.
Batman Smash Challenge: 3 / 3
Equip Cyborg with his Sonar Suit and shatter the LEGO glass stalagmites to reveal some LEGO bricks. Build these bricks into a sprinkler.
After the sprinkler has run its course, three mushrooms appear. Use them to bounce your way to the platform above. Once on the platform, fly to the top of the vault in the upper right corner. Stand on the switch to open the doors below, revealing an electrical terminal in the process. Equip Cyborg with his Electric Suit and discharge the energy from the terminal.
Objective 3: Charge the Terminal
Now carrying a charge, drop down to the ground level. To the right is another set of stairs. Climb them and smash the LEGO rock that blocks your path. These bricks can be built into hyper strength handles. Once you have built them, have Cyborg rip the stone from the nearby wall. An inactive electrical terminal was hidden behind there!
Equip Cyborg once again with his Electric Suit and charge the inactive terminal. Once you have done so, the path ahead clears so that you can exit the level. Of course, there are some guards that come to interfere with your escape, but they shouldn’t be a problem for you.