Well, I played through the game in about 3 hours, and it felt like a chore. There are only really like 6 instances where you have to actually play the game, the rest is spent searching for the objectives and keys to unexplored rooms. You can just run straight past and through all the enemies except bosses and there's no benefit to fighting them. I have a few scenes still locked - you have a choice to inject yourself or the girl you rescue with the antiviral seyrum or whatever (that can be mixed with aphrodisiac) which I imagine accounts for one, but I'm not sure about the rest. There's an optional scene in one of the bathrooms, but I'm not sure if there are others and if so, where they are and at what part of the game. Also, you can get food items (heal 25hp) by interacting with the posters around the building.