Ninjahtic is an action/adventure platformer with elements of puzzle-solving and stealth. While it's progression is linear, the open-ended nature of every level requires exploration of an abandoned civilization located atop floating islands.
Achievements have been added along with Japanese language support. You may need to reinstall the game if you haven't received this update. The current version is 1.2 and can be checked in the game's folder.
Also, this is probably annoying but while this game now has a Japanese translation, I'm currently unable to properly translate everything on the store page. This is due to this game not having any text displayed outside of the menus and loading screens, so I only needed to translate those to make a Japanese version of this game. I will translate the store page when I'm able to.
Thank you for all of your patience and support!