The player takes control of The Lodger and helps him survive by turning the lights on in every room of the house.

There might be, for example, a clock which can help speed up the time, a place where The Lodger can hide, or just some decor items.

The developers claimed that Knock-Knock's design was sent to them by an outsider, and that the production followed his outline.

[5] The team based the game's design on the concepts of "obscurity and inevitability", which the company's Vasily Kashnikov called "the two greatest fears".

Dybowski remarked that Ice-Pick had to remake "the game twice from scratch" before it managed to strike the right tone.