i take no credit for the guide here is where it comes from http://www.cheatcc.com/pc/sg/lego_batman_2_dc_super_her....txt
Super Hero at 55,000
Characters: Batman, Superman (low power)
Rally Grounds -
Ah, the foolish masses. So easily swayed. Head to the left and knock down
the glowing lights so you can assemble the Power Suit. Next, burn down the
gold wall to the right, then rocket the silver pipes behind it. Freeze the
waterfall and climb up.
Head to the right past the big TV and burn the gold part on the right side.
This will release some pieces for an Elec Suit, so take it and climb up the
electrified ladder. Take power from the generator so Superman can follow,
then pull on the orange handle to make a ramp up to near the robot's arm.
Pull down the pull handle on the arm, then climb the ladder and have both
characters stand on the buttons. Once the robot moves its arm, burn up the
gold flower on its chest.
City Hall Rooftop -
Well, the Joker gas is gone, but you've still got a rather formidable robot
to deal with. Assemble the helicopter on the right, saving the rotors for
last. Once it takes off, grapple up to it then hop in. Maneuver the
chopper so that its searchlight shines in the robot's eyes.
For the next part, head to the left and burn down the gold wall. Head
through as Batman and take the Bat Suit. Glide to the right and assemble the
pieces into a spotlight and a generator, then use sonic on the glass to make
a ramp to get back up here. Now, head back and take the Elec Suit, then
charge the generator and commandeer the spotlight. Shine it on the robot
again. Lastly, walk up to the flower on the robot as Superman and pull on
the orange handle.