https://www.speedrun.com/mr_driller was the original category for this game, however it turns out there are some key differences between the Gameboy Color / Wonderswan Color version of the game and the PS1/PSP/PSV/PC/Arcade version of the game.

Apart from a different UI, the non-GBC/WSC versions have a difficulty setting that speeds up the game significantly, meaning that GBC was technically unable to compete with the other platforms for topping leaderboards. So I submitted a separate category for fairness sake. And here it is!

There are other minor differences between the two, but they aren't super important.