It's time for the final mission. Use Cyborg to destroy gold box on the right (picture). Use bricks to build platform with electrical suit for Batman. Jump on the robot's left hand and plug to the electric device.
After explosion use Wonder Woman's whip or Batman's hook on two handles which will show on the arm of the robot (picture). After that jump on platform near robot's shoulder and pull golden grip.
Move left and set green bricks with Green Lantern. After that use Cyborg's laser on the golden wall (picture), pull two handles and use magnesium on two blue bricks.
Use bricks to build platform with acrobat suit for Robin. Throw pole into robot's right shoulder (picture) and hang on it. After that use Green Lantern to build a hammer.
When Jokers leaves robot attack him (picture). If he paralyze one of heroes switch on another character and punch him. In break between normal fight you will also have to eliminate smaller enemies. Repeat this tactic until you defeat Joker.
After fight with Joker you will have to face with Lex. At the beginning quickly hide behind one of black crates on the right and wait until enemy destroy it (picture). Repeat this action until Lex destroys all crates and use bricks to build terminal.
Get on the platform with Robin's trackball and start aiming Lex. Once you have done this press and hold H to activate laser (picture). You have to aim Lex and attack him in this way all the time (sometimes he will try to run away but don't worry, just execute this tactic).