"Chzo Mythos" is a series of games developed by Yahtzee, which consists of 5 Days a Stranger, 7 Days a Skeptic, Trilby's Notes, and 6 Days a Sacrifice. The games were made over a period of 3 - 4 years on the Adventure Game Studio engine. The games are horror-based and are heavily influenced by Silent Hill with other game references thrown in. He used to offer the Special Edition 4-pack of these games (including developer commentary, soundtrack, and other extras) as donationware for a price of $15, but has recently released it as freeware.