One of the few budget first-person shooter's worth playing.
The Microsoft Windows PC version of Nosferatu: The Wrath of Malachi is on sale for $1.01 (66 percent off) on Steam as a "Week Long Deal" that ends May 21, 2018.
Nosferatu is a non-linear survival horror first-person shooter with a random architecture generator, that changes the layout of the castle and most characters when you start a new save file.
Although it only takes 4 hours to beat the the main story, the random architecture generator changes enough things to keep you coming back for more vampire killing action. Here's a trailer for the game: