Shown throughout the game at loading points between floors is Isaac recollecting about his childhood while curled up in a fetal position and crying. Isaac then puts the paper he was drawing onto his wall, which transitions into the game's title screen. He finds a trapdoor under the rug, and just as his mother bursts in, he opens the trapdoor and jumps down it.

Isaac is watching through a sizable crack in his door and starts to panic. She obliges, grabbing a kitchen knife and goes to Isaac's room. It states she has done well but says it still questions her faith and commands she must sacrifice Isaac. Once again, she follows its command and locks Isaac in his room. The voice again calls out to Isaac's mother, stating Isaac must be isolated from all the evil in the world.

She obliges, taking away his toys, pictures, his handheld video game console and even the clothes on his back. It asks her to remove all sin from Isaac to save him. Isaac's mother then hears 'a voice from above', stating her son is corrupted with sin and must be saved. Isaac (a kid) and his mother live in a small home situated on a hill, both peacefully keeping to themselves, with Isaac drawing doodles and playing with his toys while his mother watches Christian broadcasts on the television. The Binding of Isaac's storyline is based off the eponymous Bible story. Each floor of the dungeon ends in a boss room, where the player must defeat the boss before being able to go down to the next floor. Along the way, the player can collect currency to buy items from shops, keys to gain entry into special treasure rooms (as well as special golden chests, libraries that contain book items, and shops), and new weapons and power-ups to increase his chance of surviving.

On each floor of the basement below, the player must fight off monsters before he can go into other rooms. The video game's gameplay and style are inspired by the dungeons of The Legend of Zelda series, while mixing in randomly procedurally generated floors akin to Roguelikes (like traditional roguelikes, death is permanent and the player is forced to restart with nothing if they die) while doing this is in a simple Legend of Zelda like formula. The Binding of Isaac is a two-dimensional Action-adventure game where the player controls Isaac or six of the unlockable characters as he traverses through the dungeons located underneath his mother's basement.

Binding of isaac the stars