you earn badges simply by playing the game. badges unlock after doing certain moves/shooting enemies etc.- example- grinding. after you have grinded for a while you will get a badge. wall running, bounce jumping, style points etc. the tally for your actions is saved both on chaos mode and single player. they level up slowly. once you unlock a badge you can equip an overdrive ( another achievement will pop as soon as you check your badge and assign your overdrive "Unlock an Overdrive")- I was about 6 hours in when I got my first badge- in single player- for lots of bounces. after my first badge unlocked about 5 more badges unlocked within minutes.