I'd tried out Ninja JaJaMaru-kun on Nintendo Switch Online not that long ago, and somehow I was expecting Mappy-Land, another NSO title, to be a similar Japanese-only arcade-type of game. I think somewhere in my head I must have been mixing it up with the original Mappy game, although I don't think I've ever really played that game much. Maybe I'd seen it on some Namco compilation? Anyway, Mappy-Land was actually released on NES in the US, so I was wrong on both counts.
Mappy is to Mappy-Land a bit like the original arcade Mario Bros. is to Super Mario Bros. in that it's much more evolved, both graphically and in terms of the gameplay. In the original Mappy it seems like there's not a lot of variety as you play as the eponymous Mappy and bounce off of trampolines, recover stolen treasure, and avoid the cats. There aren't a lot of options in how you can avoid the cats, and that's one of the best things that Mappy-Land improves upon. In Mappy-Land you still have the same basic premise, but there's variety in the stages and you can now collect usable items that distract the cats, such as a waggling wand toy or a bouncing fish, and these prove to be extremely useful (although sometimes a little difficult to use). In the original there were only very basic environmental mechanisms for eliminating the enemies (namely, two different types of doors), but in Mappy-Land each stage has its own unique environmental items, such as rolling balls, canons, or high bars that you spin on. These also greatly add to the fun and balance of the game.
The first stages go by quickly and are easy to beat, but the game gets progressively harder. The game has four sets of eight stages, and although the locales repeat, the layouts are all different and contribute to the increasing difficulty. There are two different types of stages mixed into the set of eight, one where you climb on vines and navigate moving trampolines for part of the stage (which just ends up being awkward, frustrating, and annoying) and another that has you using balloons to soar the skies and defeat ghosts with the help of a ray gun. There are also extra parts to some of the stages mixed in periodically that extend a playthrough where you have to collect an item, such as a train ticket or a cross, to complete the stage, and these extra parts increase as you progress through the game. The third and fourth sets of eight get really difficult and basically require memorization of the stage layout and careful use of your items, but a built-in level select keeps frustration low, and having the save states of Nintendo Switch Online is a much-appreciated modern convenience.
In terms of the gameplay Mappy-Land is pretty solid and fun, but it's really the graphics, music, and "theme and fun" that elevate it and make the game a memorable experience. From a modern perspective most people would probably feel like the game is pretty basic, but it's a polished title for its time (it was released in Japan in 1986) and as a fan of retro games I quite enjoyed it. It doesn't look like the series really caught on in the US, although it seems like there have been some other Japanese-only sequels over the years. Anyway, I'm definitely going to have to go back and try the original now at some point anyway.