quick translation of the menus:
title: Start/Help
main menu (left to right, from the top): Easy, Medium, Hard, Grade Certification - you'll be shown a short
tutorial after selecting your first level, won't appear after that.
grade certification menu: Platinum, Gold, Silver, Bronze (not sure about this, none of them were selectable)
in-game, the red button under the numbers erases the selected space. the green left and right arrows are basically undo and redo functions. buttons in the bottom right are save (allows you to save during a game and resume later) and options.
options menu, from the top: erase all data, quit game, bgm, background colour, input mode (panel/draw), retry, exit menu.