The game got a rebrand when the second set of characters came out, some changes to the character gear pieces and 'legendary' challenges. Suffice it to say that anyone looking to get this wants the version that comes with the extra characters. CDKeys has it selling for £7.49 right now.
Bought this deal earlier and just loaded it up and the title screen says its the legendary edition. Definitely only bought the basic version though. (confused)
Better to get the Legendary Edition since that comes with an extra 8 characters. Unless for some reason you don't want to play as the Teenage Mutant Ninja Turtles.
Cdkeys are spoiling us today!