The new(?) thing for some retro game devs is to require their games to run in emulators set at 1000% speed. Because they would be unplayable on normal settings or a real machine. This is one of those. I still managed to get to lv 17 or so (at 2.5x speed) and enjoyed it a fair bit, despite unfair situations etc.; but the hilarity of the jumping animation (is this castle on the moon?) alone makes it worth playing for a while, I think.