This really feels like one of those hard-core platformer games. That being said, I kinda hate having to go into the room with the Elder Ninja to get a katana every run. And was Muscle Ninja suggesting that I f*ck the walls???
You can save the game by interacting with the gravestone, it starts flashing after you get the katana. Muscle Ninja's dialogue has some innuendo as a joke, but it could mean anything