Movement and the environment felt good - the level design was just confusing enough to be a stressor without actually being a problem. The flashlight battery timer was neat, as is the combined combat mechanics of light dissipating the shadow men and the floating knife minigame (although it took me one death to figure out what was going on). Almost reminds me of Spectrobes, in a weird way. Not too long, either.
Here's my playthrough, so you can witness my trial-and-error: