Knock Knock is a 2D side-scrolling survival game set in a single house in the middle of the woods with a single resident. The game was started by Ice-Pick Lodge when they "received an anonymous e-mail which suggested that we should produce some 'unconventional' game based upon the materials attached to the letter." The attachment contained text snippets, scraps of audio files, and video fragments. All of which were in an archive that was titled "Lestplay." The full story for the games initial concept can be found at the game's official website.

In Knock Knock, you take control of the resident of the house as he moves through it trying to avoid losing his sanity to the creatures arriving in the house, as well as trying to find the answers to his missing memories. The game has a simple control scheme using only WASD or arrow keys, the E key, and the space bar to control the main character. The simplicity of the controls does not take away from the amount of strategy and thought required to survive the 'visitors' until morning. Each room has a light source that will banish any creature in it, with a small cost to your sanity, which is measured by a clock in the top-left corner of the screen. This clock also measures how much time is left till sunrise and can be sped up if you find special items in the rooms. Some of the rooms also have a place you can hide behind to safely allow the visitors to pass you without stealing your sanity, but hiding in them will reduce your sanity at a slower rate, meaning you can’t just hide forever.

You can fix burnt out lights and open closed doors by holding the space bar but you will remain still for a couple seconds while doing so. You can abandon your actions by releasing the space bar if an enemy starts to get too close. Repeatedly banishing smaller enemies will make it impossible to progress to morning and will in fact force you to completely lose your sanity if you do it in rapid succession. The fastest way to morning is to avoid the creatures as much as possible and search out the special clocks that speed up your own clock. To do this you must turn on lights in rooms in order to illuminate the items in each room. As you progress through the levels of the game you will be greeted by pages with instructions on them. If you decide to follow these instructions in real life, feel free to explain your experiences in the comments below.

Knock Knock doesn't use much music for the game but makes up for it by using several creepy sounds such as knocking, glass breaking, various ominous sounds, and several voice-overs to drive the chills up your spine. The visuals are dark, yet easily discernible in the areas without lights. This adds to the chills when something happens to the light in a room that you are currently in. Having the lights burn out on me just before something fades in on screen and starts creeping towards me was almost too unnerving for me. Almost…

If you are like me and you get attracted to games like Slender or Amnesia but find it difficult to sit through them, even when other people are in the room probably screaming at things more than you are, Knock Knock is definitely a game you should pick up. It is currently available on Steam for $10 for PC, Mac, and Linux.

Knock Knock was developed and published by Ice-Pick Lodge. The game currently retails on Steam for $10. A beta copy was provided by the publisher for review purposes.