GnG actually has a surprisingly generous checkpoint system for an NES game, and it looks really nice for 1986, so I got pretty far before I reached a difficulty threshold that made me want to kill myself. It does offer an enormous sense of satisfaction for overcoming its clumsy rhythms and bizarre enemy designs, and also it's funny that every weapon in the game is worse than the one you start with, but it's only worth your time if you enjoy suffering as much as me