A bit of a light experience for 4 bucks but it's an utterly unique experience that I'd say is worth it. In terms of directly attempting to scare the player very little is actually done outside of the near silent halls with only footsteps and the ambient hum-buzz of the fluorescent lighting. Instead, the game's deceptively simple set of instructions instills a sense of paranoia and invites inspection of it's details so closely that any escalation becomes shocking.
I haven't played anything quite like this before. It ended up being surprisingly immersive being forced to pay as close attention to the game environment as possible. This turns out to be a mostly enjoyable horror-ish game of "spot the difference," but I will say that some of the differences were so subtle that they were almost frustrating when missed. Cool way to burn an hour and I enjoyed seeing some of the wackier anomalies.