I cannot read, write, or speak a word of Japanese. That being said, my Wonderswan purchase was probably more for esoteric value and not for its game library; unless my aim was to learn Japanese. If that was the case, then I failed miserably. Nearly every title I've come across is a text-heavy role-playing game that I just can't get into, flashy graphics aside. I was quite surprised by Mr. Driller, though. Although my version is an import (I don't know that it had an American release) it's a very straight forward puzzle game with few options, so it's quite easy to figure out and get into.
Basically, you guide your character downward while drilling through multi-colored blocks. The blocks are arranged in various shapes (similar to Tetris), and drilling causes the blocks above you to fall and possibly crush you; similar to Tetris from Hell! In addition, your character must continually collect air tanks to stay alive. The air tanks are usually amid stacks of exploding boxes. Drilling through these boxes causes you to lose 20 air points, so the best strategy lies in freeing the air tanks by drilling beneath the boxes and getting them to fall out of the way.
The game includes three modes of play: drilling through 500 meters (five stages), 1000 meters (ten stages), or simply going for broke and drilling until you can't s drill no more! The last mode, graciously enough, lets you set the difficulty before you begin. On a whole, the difficulty is of the tough but fair variety; easy enough at first to get you hooked, and progressively challenging enough to keep you coming back.
I understand this game is available for other systems (the DS version immediately comes to mind), but if you're like me, you're a young sexy gamer who's tired of playing Final Fantasy for the twelfth time and want to get a few more miles out of your Wonderswan. If the aforementioned notion of Tetris from Hell appeals to you, you can't go wrong with Mr. Driller.