Spotted on DLsite - an entry in the "#@*$&!" genre of platformers (I'm sure there's a better name, but you know what I mean... The ones where everything is a trap and you die constantly.)
It has cute adorable graphics. You have infinite (negative) lives. You die a lot.
There's a free trial, and once you manage to launch it (.net required) you can probably manage even without any Japanese knowledge. Arrow keys and Z/X/C will get you through most Japanese platformers... You won't be able to read the instructions, but they're probably lies anyway!