Mr. Driller Ace is a Puzzle game, developed and published by Namco, which was released in Japan in 2002. It was translated into English by Keep Smiling International. The fourth installment in its Mr. Driller series, players control one of seven characters and must make it to the bottom of the level by destroying colorful formations of blocks. A adds several new mechanics to the gameplay of its predecessors, such as a virtual pet named the “Pacteria” that players can grow and care for.
Mr. Driller A is a puzzle game similar to Puyo Puyo (1990) and the classic arcade game Dig Dug (1982). Players choose from one of seven characters to play as: Susumu Hori, the protagonist; Ataru Hori, Susumi’s self-contained older brother; Taizo Hori, the protagonist of Dig Dug; Puchi, Susumu’s dog; Anna Hottenmeyer, a rival driller from Germany; and Holinger-Z, a drilling robot. In each level, players must make it to the bottom of a well by destroying, or “drilling”, colorful formations of blocks.
Destroying blocks results in those above it falling and connecting with similarly-colored ones; should four or more matching blocks connect, they will be destroyed, which is useful for creating chain reactions. Blocks will also fall if there is nothing underneath to support them, which can crush players who are underneath them. Players will need to manage their constantly depleting oxygen, which acts as both a health bar and a timer. Oxygen is replenished by collecting blue air capsules, while oxygen is lost by destroying brown X-marked blocks.
If a player is next to a block with an open space above it, they can “jump” up that block. A adds multiple mechanics and concepts to the core gameplay of the series. The main gamemode is “Dori Dorado Ruins”, which features Susumu donning a knight’s armor and venturing into ancient ruins. In this mode, the player’s oxygen meter does not deplete on its own, but instead drains by 1% each time a block is destroyed. Susumu can find houses inhabited by blue creatures named Undergrounders to learn tips and secrets.
He can also enter shops to purchase items, such as those that increase his movement speed and a protective shield; these items are purchased with “mileage points”, which are earned based on how far the player has gotten in the well. At certain points, Susumu will engage in RPG-esque combat scenarios with Dig Dug enemies Pooka and Fygar. By collecting fruits and vegetables found throughout, the player can feed these to their Pacteria, a gelatinous-like virtual pet that can evolve and grow. The player can transfer their Pacteria pets to the GameCube game Mr. Driller Drill Land for use with certain mechanics and modes in the latter.