knock knock is a unique, beautiful, sidecrolling, psychological horror game. the gameply involves your character, who is going insane, trying to hide from ghosts long enough each night to make it to morning.
the game is opaque and gives you only some vague advice on what to do. the gameplay mechanics also seem to be inconsistent, which is actually one of the game's strengths, you really don't know what to expect, and it creates an atmosphere of tension.
sadly, the game loses its luster after the first hour and a half or so, and the game also introduces a game-breaking timer which will literally cheat you out of playing the last level and getting a decent ending. you'll have to replay the entire game if you want the good ending, which is not an enjoyable prospect, as the gameplay gets very repetitive after a couple hours. for a game based largely on story, this is unforgivable.
another complaint is that, after a while of playing, you'll find that many in-game events are random; for instance, i was trapped in the initial room several times, then pinned by several ghosts. this alone killed my entire sanity meter, i tried several ways of getting out, but nothing worked. levels are either too easy, or they'll flat out cheat you, regarless of how well you're reading the shifting mechanics. sometimes randomness is good, but here it often hurts, and reduces the quality fo the level design.
it's too bad, as the art is lovely, the atmosphere is creepy and interesting, and the gameplay itself is novel.
i also honestly question the integrity of the reviews here on steam, this is a deeply flawed game sporting a 57 rating on metacritic, it's hard to believe that others weren't equally frustrated by some of the game-breaking features.