Revealing mistake: Baxter Building: Just as Captain America and Mr. Fantastic are about to land on the ground after jumping off the Helicarrier, Captain America's shadow doesn't match up with his distance off the ground.
Continuity mistake: Sand Central Station: Abomination is thrown through a station window and the glass flies out as he is thrown through. No glass is shown on the ground.
Continuity mistake: The Hulk is shown shirtless, yet if he transforms back into Bruce Banner, his shirt is still with him.
Continuity mistake: During the intro clip, one shot shows Tony inside his suit with blonde hair. Later on during the intro clip for the "Sand Central Station" level, he is shown inside his suit with brown hair.
Chosen answer: Captain America has a shield. Use his shield to deflect the blasts from the turret and it will bounce back at the turret destroying it. Left over from the turret is a piece of rubble. Switch to The Thing and have him throw the piece of rubble at the part of the wall that is glowing. This will uncover a target for Captain America to throw his shield. Switch back to Captain America and have him throw the shield at the target. The electric gate will be disarmed after this.
Casual Person