I'm going to give this action adventure/platformer-with-RPG-elements an '8 out of 10'.
I played through and beat this game recently, and I really enjoyed it, although I do not understand Japanese. The gameplay is simple enough to understand and I beat the game without ever understanding what some of the shop items were. This game is basically a side-scrolling platformer with a couple of vertical levels. There is even an underwater forced-scrolling horizontal shoot-'em-up stage for variety. You have your basic sword weapon which shoots projectiles to destroy enemies. You can upgrade your sword and projectiles by saving up coins to purchase a better weapon at the next town. There is a town at the beginning of each stage where you can purchase various items from shops. Enemies respawn, so if you want, you may 'grind' to save up coins to purchase items. At the end of each stage there is a boss fight.
Overall, I must recommend this game, although the item/menu screens were intimidating at first, since they are all in Japanese. On Pcenginefx, sunteam-paul posted a simplistic translating of this screen which helped me get past the entry barrier.
On the plus side, I really like the cutesy atmosphere and humor, it looks damn nice, and they showed some creativity with the platforming elements. On the negative side, I'm not sure if the whole buying items thing really worked, since it just meant that you'd feel like you had to grind until you had the best weapon and armor, and it probably would have worked better if the enemies dropped healing items sometimes like a regular platformer. However, the biggest issue is that the platforming felt a little imprecise. It's one of those platformers where you need to build a little momentum to get a proper jump going, and it can be hard to tell if you've got enough sometimes. It's good, and it definitely worth getting at the rather low price it goes for, but that issue keeps it from being on the level of a Mario, Sonic, or even a Bonk title.