The objective of Mr. Driller Online, as with any Mr. Driller game, is to drill to the bottom of a long, vertical pit filled with blocks of varying colors. Susumu or a variety of other characters can move left or right, fall down, and climb one block at a time and no more than that. The player can drill in any direction. Colored blocks will clear when the player drills them, causing other blocks above them to shake in warning to the player and then fall. If blocks fall on top of the driller they will crush them and the player will lose a life. The driller also has a limited oxygen that will deplete over time. The player can get it back by picking up air capsules and special items along the way. The player will lose a life if their air runs out. The game is over when all lives are gone or the player reaches the bottom.
Mr. Driller Online features two single-player modes, Arcade and Challenge.
- Arcade mode presents the player with the normal gameplay to conquer five levels that only really differ in look.
- Challenge mode adds random challenges to each section of the level, such as completing the section within a certain time limit or picking up a limited number of air capsules but the game still only has the same five levels.
Additionally, the game also has online ranked and unranked multiplayer matches. Online players can participate in Versus or Tag Team modes.
- Versus has two players compete for a highest score within a set time.
- Tag Team has two teams of two players battling against each other.
There are also online leaderboards.
There is no local split-screen multiplayer for this game.
Mr. Driller Online was included in Namco Museum Virtual Arcade.