Knock-Knock, a horror-mystery survival game, has just gone on sale for $0.69 when you factor in the Amazon coin reward. The game is $0.99 with a 30 coin reward. This game was free once several months ago during one of Amazon’s big bundle giveaways, but has otherwise never been on sale. In this game you must survive the night by hiding from invading creatures, all while trying to solve the nightmare’s mystery. It’s compatible with both the Amazon Fire TV and Fire TV Stick, but does require a game controller to play.