Solve 55% of riddler challenges

The player has completed the game without harvesting any Little Sisters

The player has either Harvested or Rescued every possible Little Sister

The player has purchased every slot in one of the Plasmid or Tonic tracks

Fully upgrade four weapons

The player has entered Sander Cohen's personal quarters

The player has fully upgraded two weapons

Complete story mode on Easy difficulty

Ride Titan henchman and knock down 10 thugs (any play mode)

Venture into Killer Croc's lair and come out alive

The player has fully upgraded one weapon

Defeat two Titan Henchmen at once

Capture and lock up Harley Quinn