If you dug the old NES game PunchOut, then you will surely like “kirton’s” interface. He took a foam filled bag with impact sensors then wired them to a PC game pad. This transfers the impact of the game through an NES emulator. The software also includes visual feedback as the sprite turns pink when hit and an LED indicator flashes. Eventually, he wants to include a strobe light to emulate character disorientation when punched. You can get all the details on Instructables.