Pause the game and go to the award screen. Here there are awards that you can unlock by completing different tasks:

Honorary Deputy - Assist 25 police officers
Superhero - Attain 100K hero points
Mega Hero - Attain 200K hero points
Silver Medalist - Beat all challenges
Gold Medalist - Beat all the challenges' mega times
Lover not a Fighter - Complete all 10 of the Mary Jane Missions
Employee of the Month - Complete all 20 of the Pizza Missions
Shutterbug - Complete all 6 of the Daily Bugle Missions
Hardcore Gamer - Complete all arcade games (with top scores)
Tentacle Wrangler - Defeat Doc Ock in story mode
Alien Buster - Defeat Mysterio in story mode
Big Game Hunter - Defeat Rhino in story mode
Shock Absorber - Defeat Shocker in story mode
Drenched Explorer - Find all 130 Bouy tokens
Knowledge Seeker - Find all 213 Hint markers
Vigilant Explorer - Find all hideout tokens
Watchful Explorer - Find all secret tokens
Towering Explorer - Find all skyscraper tokens
Sucker - Foil 25 ambushes
Watch Dog - Foil 25 break-ins
Stick Up Artist - Foil 25 robberies
Peace maker - Prevent 25 gang wars
Thug Mugger - Prevent 25 muggings
Game Master - Receive all awards/ 100% Completion
Lifter of Spirits - Rescue 25 hanging citizens
Human Ambulance - Resolve 25 medical emergencies
Life Preserve - Resolve 25 sinking boat crises
Friend to Children - Return 25 balloons to children
Partycrasher - Stop 25 battle royals
Automobile Avenger - Stop 25 car jackings
Bane of Petty Thieves - Stop 25 purse snatchers
Anger Manager - Stop 25 road rages