The Binding of Isaac is a shooting roguelike action RPG game wich is horror sci fi themed. Plot:
You can play as Isaac but you can unlock other characters with special skills, for example Isaac can attack with a orbital soul around him that shoots rapidly. Isaac's starting equipment is a knife and the unlockable soul. The dungeons resemble the labirynths from Zelda games with various types of keys to open passages to other rooms. The enemies can vary but they are all very creepy, the bosses are even worse. The game is randomly generated and you have to start over when you die. You can unlock multiple endings depending on the final boss you have defeated, with a mod you can unlock the true final dungeon and the true final boss, leading to the true ending and acquiring the 100%.