This is a really nice, concise, and fairly challenging game. I think the designs and overall style is really good, and set a mood that I enjoyed. The gameplay loop was pretty basic, but I still enjoyed playing it and liked how it had a mix of offensive and defensive mechanics if that makes sense.
The game was also fairly spooky, the first time plays of most of your games always have one or two things that creep me out or straight up scare me. This game's stand out moments being one of Tinky's desk phases and of course Dipsy busting down the door. Even if the latter didn't phase me after a couple times, I thought it was a really cool and visceral way to choreograph the need to put on the mask
In terms of general critiques, I do think the difficulty curve is a little strange. Nights 1-3 were quite easy, but 4-5 were a more reasonable challenge. I don't think the latter two were too difficult by any stretch of the imagination, but it was a bit jarring to me personally. Night 5 took me a few tries until my friend joined and was trying to talk to me and I said "hold a second." like Dexter Morgan and beat it because I have aura like that.
I also think the ambience was a wee bit lacking. The visual style itself is great, but I think some more spooky audio would have helped the game a lot and would have made me feel more immersed. Maybe there was a fair amount of ambience, and I just didn't notice due to listening to Po 24/7.
LAAAAAAAAST thing. I wish the "boss" was a little harder. Honestly felt a little boring after night 5. Doesn't mean I didn't think it wasn't cool!
Overall I think this is a really nice little fangame and I quite enjoyed it!!! Yippie!!! My overall critiques just equate to wishing that the difficulty kicked in earlier, and that the experience was overall a bit more "potent" (vague review words, my favorite! Next I will call the game "floaty" or "starchy")
Cannot wait for another project from you : )