Source Game: Binding of Isaac
A young boy was happily living with his mom. His mom watched Christian television while her son played with his toys. One day, Isaac's mom heard the voice of God and was compelled to start ridding Isaac's room of sinful temptations. Before long, God presented Isaac's mother with an ultimatum: "Kill your son Isaac to prove your devotion to me". Fearing for his life, Isaac ran into the basement...
Gameplay overview here