If the game freezes, just click inside it (games can get unresponsive if you click elsewhere on the page).
Save the people on the streets below by catching the wreckage that is falling from the building.
Use your Arrow Keys to steer Left and Right smashing as much as falling debris as you go, but watch out for any kryptonite! Once you've caught the wreckage, start tapping your Up Arrow Key to slow superman down and safely dispose off the wreckage. But be quick, the ground is fast approaching!