In this video, the concept of “code injection” in Tetris is explored, where specific controller inputs during gameplay can be used to alter the game’s behavior. This is demonstrated through the use of high score tables and specific controller inputs at crucial moments, which can lead to a change in the game’s execution path. The focus is on a specific crash point in the game, which occurs when a certain routine, called the “jump Handler,” is interrupted during its execution. By manipulating the interrupts and the values of certain memory addresses, the speaker shows how to redirect the game to a different execution path, effectively “reprogramming” the game. This is demonstrated on an emulator and then on real hardware.