this demo is a remake of the 1st level of metal gear solid. you can walk around the boat, fire your gun, take rations, etc. there are no bullets so you can not kill the 1 enemy found on the level.
Or when your player dies, you can say in code, if enemy exists, do nothing, but if enemy does not exist, then create enemy at certain spot. (This would be a pain tho for lots of emeies)