Full list of all 12 Sneak King achievements worth 200 gamerscore. It takes around 15-20 hours to unlock all of the achievements on Xbox 360.
Achieve an 'A' Rank for all Challenges in entire game
Complete all Challenges in entire game
Unlock all levels
Complete any 40 Challenges
Achieve an 'A' Rank for all Challenges in one level
Complete all Challenges in one level
Unlock Cul-de-Sac Level
Score 100,000 points in a single delivery
Hide 100 times in total
Achieve an 'A' Rank
Perform a Level 3 Flourish
Beat 1 Challenge