The only time i have trouble sneaking is the first mission because you don't have Powers yet after that i just Choke everyone using Blink and Slow Time (these two is all you need if you're going for a Pacifist and Shadow playthrough)
@guildclaws I would like to get all the achievements so I am going to have to find some way to sneak past everyone in the beginning too...then there is the achievement for playing all the way through only buying the blink power...I think I may have to play through two more times at least. Just finished it today but have got the DLC and was attempting one mission but got caught lol...will have to try again next time lol.



