You play the game as Susumu or Anna, equipped with a pressurized suit and a drill, in search of the King of the Undergrounders. To achieve this goal, you'll need to drill down thousands of feet while avoiding crushing forces and managing air supplies. This is a real-time puzzle game where you'll constantly move downwards or sideways in an effort to reach the bottom. As you dig, blocks will fall into place to fill the spaces below.
Blocks can be colored and will stick together when they form sets of four or more, giving you time to rest. However, if three or more blocks come together, they'll disappear quickly, leading to chain reactions that can become dangerous in two-color levels. The game features three modes of play: Story, Time Attack, and Endless Driller.
Story Mode follows the basic plot, while Time Attack presents a set number of levels with a time limit constraint. Endless Driller allows you to continue drilling as long as possible without any limits.