I like the Art, the use of color and lighting makes for an oppressive atmosphere. The gameplay is very responsive. The automatic hiding mechanic i especially like.
While turning the guards around with the camera is interesting, walking by them while they're stunned would be better also because it takes 2 films and you don't have many.( i ran out in the 2nd level but that was on me because i didn't look in the top left corner :P)
Also a count how many posters you have left in a level would be good.
All in all a very interesting and well made game for such a short time. I can see the concept getting developed further.