Bugs Bunny Crazy Castle II was a 1991 puzzle-platformer game by Kemko. In each level, Bugs Bunny was tasked with opening the door to the next level, with the ultimate goal being rescuing his girlfriend, Honey Bunny. The door was locked and required keys that were spread around the level. Unlike a Mario game, Bugs Bunny could not defeat enemies by himself. In fact, he couldn’t even jump. There were some items he could use to attack enemies or get by them alive, but most of them were limited use.
These two things made Bugs Bunny Crazy Castle II like a puzzle. It wasn’t just about finding the keys but also finding a safe path there. Many levels had unlocked doors that basically “teleported” Bugs Bunny to another location in the level. Most levels couldn’t fit all on one screen, so they could become complicated mazes to navigate, all while having to avoid enemies. The difficulty was pretty much perfect. It was hard to get through the whole game, but the developers gave the player enough extra lives and tools to make it through without too much frustration. It probably took me a couple weeks to beat it, but I can’t remember in detail.
The only bad thing about Bugs Bunny Crazy Castle II was there was no replayability. Once I beat the game, there was nothing else to do but play the exact same levels again. A modern game in this style would include a level editor with support for online distribution. That would truly make the game endlessly replayable. This sort of thing is possible now on the Nintendo 3DS but not back on the old Game Boy. The game did as well as it could have at the time though.