SMS Plus PSP is a Sega Master System and Game Gear emulator for PlayStation Portable.

Release notes:

SMS Plus PSP now includes the Time Rewind feature I mentioned earlier. To enable it, map any button to ‘Special: Rewind’. The feature alone takes up 85% of PSP’s memory, and I’m unsure what ramifications this might have for certain configurations, but if you come across problems, let me know.

Approximately 20 seconds of recent gameplay is saved, and saving is done once every five frames.

Thanks to for the news.