Hourglass lets you run supported 32-bit Windows games in a mode where you have additional tools at your disposal, such as the ability to speed up or slow down or pause time or even revert the game to an earlier state to undo a mistake. It also creates a deterministic record of the buttons you press in the game that can be played back at normal speed while the game is being encoded to a high-quality AVI. It acts like a re-recording emulator for Windows, but it lets games run natively instead of emulating them.

Hourglass is best used with Windows XP, and does not support mouse input. It is not being actively developed anymore. A revival project called Hourglass Resurrection was attempted, but ultimately deemed infeasible; see this forum thread for more information.