An exercise in tedium. But it inspired so many great games that It gets the legacy impact extra half star. But if you want a side-and-vertical scrolling hard as nails platformer on the NES you're better off playing Kid Icarus. I actually played this through once to the end, but hated most of the experience. The moments of discovering a secret on your own without help do feel great though. I bet kids in the 80s loved that.