Challenges have returned in Borderlands 2 and this time they came to play. Nearly everything you do in Borderlands 2 will be recorded. From exploration, using certain guns, killing particular enemies, using certain types of damage, and everything in between.
This time around however these Challenges award you a 'Badass Rank', which in turn rewards you with 'Badass Tokens'. These tokens can then be redeemed for stat bonuses (14 of them to be exact).