Knock-knock is a deeply unnerving game that manages to succeed at what it sets out to do.
From the start you get to meet the charming Lodger as he briefly teaches you just how things are in his home. From there it's up to you to figure out the rest. You have six days and nights to adjust and learn, and then from there the game really begins. The time limit is pretty strict, so if you haven't figured out what you're doing by then, don't expect to survive. I barely managed on my first time with just a teensy bit of time left. Overall that stress of time and all the things out and inside your home coming after you is something that sticks with you for quite a while. Though the game does begin dull, once things speed up it truly feels like a game and all those horrifying things out there become all the more horrifying. I'd rather not say much since there are some great ideas in place and it's better to experience them for yourself than not. That's what the first six nights are for after all, just experimenting and figuring out the most effecient way of doing things.
There are flaws though, this game is heavy on RNG. Though skill can help you through most of what you're trying to accomplish, exploring the forest on a time limit is a bit much since there's no easy way to find your way home again rather than just go forwards and hope for the best. There's no guarentee that you'll figure out just what you're supposed to be doing out there without a hint or two either, though thankfully there are enough hints to make people explore the forest at least once or twice early on. Even worse, once you enter the night phases, enemies can and will spawn near you and remain there for long periods, often trapping you in a corner. Or worse, a roaming enemy will follow with it. Touching a solitary enemy is a minor time loss while touching a roamer will set you back a massive amount, but even a minor time loss is a lot here. The game's pretty well designed however and you figure out just what you should be doing before long, though there's little room for error so a few hints are always welcome.
So yeah, Knock-knock surprises though you need to give it a bit of time to shine and be patient through the less enjoyable segments. Not recommended for those who are effected by surrealistic imagry as half of this game's horror is based on that with the other half being existence and dementia based. If you think you can take it, pick it up.