Well, the closing thing to the pain of getting hit by a projectile in VR-based FPS games is using an airsoft gun according to Rated Red. It will be interesting if game developers incorporate that, but how? Watch the video... "Where’s the pain in getting shot in VR? There is none. Until now. The stars of Rated Red's 'Kill Rob Bailey' test out 'Super Hot' for VR...with Airsoft guns."