Considering Superman's powers and unique abilities, it may seem, that he has no weaknesses and fear, but it is not. His enemies are well informed about his major fear, so they will use it on the purpose.
Take control of Superman and deal with nasty scum, that filled the streets of the city. You have received a call, which informed you about the assault on one of the city buildings. There are a lot of hostages there, so be careful when you proceed in. Use your fists to deal with enemies in melee fight and X-ray to kill them in range.