The "Unblocked" version of The Binding of Isaac refers to a version of the game that can be played online, often through a browser, without the need for Flash. This allows players to access the game from schools, offices, or other locations where Flash may be blocked or restricted.

The Binding of Isaac is a popular indie video game developed by Edmund McMillen and Florian Himsl. It was first released in 2011 and has since become a cult classic. The game is known for its unique blend of exploration, item collection, and permadeath mechanics, set in a dark and disturbing universe.

The "No Flash" aspect simply means that the game can be played without the need for Adobe Flash Player, which was once a requirement for playing many online games.

The game follows Isaac, a young boy who lives with his abusive mother in a house that is apparently haunted by monsters and supernatural entities. One day, Isaac's mother receives a message from God, telling her to sacrifice her son. Isaac, fearing for his life, hides in the basement, where he must navigate through a series of procedurally generated rooms filled with enemies, treasures, and power-ups.