Overview:

In Braid the player can rewind time at will - the scene plays backward at an accelerated pace, like you might see on a VCR. Rewinding is heavily used, and higher-level gameplay concepts are built on top of it, so it was important for rewinding to be robust, exactly reproducing the game scene at each given time. Furthermore, the game design required the player to be able to rewind a large amount of gameplay (30 to 60 minutes) and the memory of this gameplay had to fit into a small space (40 megabytes on consoles). This session explains in detail how these things were accomplished and offers an understanding of what the different possibilities were, why the current method was chosen, and knowledge of many practical implementation concerns and how they were solved.