Ice-Pick Lodge announces Knock-knock is now available on Steam for Windows, Linux, and OS X, and is discounted 15% off the full price for the next week. They also offer this new trailer with gameplay, and here's an explanation of the game that knocks:

A wooden house stands in the forest. A single man lives there.

The house recieves visits from unusual guests that knock on the window inviting this strange hermit to join them in a game of hide-and-seek. To win, simply remain alive and maintain your sanity until sunrise. Approaching the Visitors head-on is a dangerous idea.

As soon as the first Visitor emerges from the forest, the countdown begins. Every passing hour brings them closer to the house, and the house's walls offer no sanctuary. Something is already inside. Something is opening the window and banging around in the kitchen. Something controls the cellar and attic. Floorboards creak softly deep in the bowels of the house.

The Visitors are well aware of your position, so you must make your rounds of the house and find the breaches that let the creatures inside while doing your best to mend them.

You may come across some useful items that might help your survival, but those items are always random and your inventory is limited to 5 slots, so your gear changes by night.

Survive until sunrise and the monsters disappear, but if they get you before the sun peeks over the horizon, well, just the idea is terrifying.