On the way, she also comes across four other diamonds: the Yellow Diamond, which was kept in the Art Museum and drove Carrie insane; the Blue Diamond, which was floating about Kuru Ruins and stirring things up (it brought a stone statue to life and even took control of a swarm of fish) ; the Green Diamond, which the unnamed police warden used to animate his massive robot, with which he battles Jill; and the Black Diamond, which gave Croog his alien appearance and unimaginable power. At the end, the Black Diamond shatters and Croog's alien face falls off, revealing it to be a mask. Croog's true face is unknown, as a head of long blond hair drops over his eyes and he runs off-screen, sobbing and concealing his appearance with his hands. At the game's conclusion, two of the Diamonds- the Blue and Green Diamonds- are stolen by the Magnet Sisters (both serve as a reoccurring boss), the Yellow Diamond is returned to the Art Museum and Jill keeps the Red Diamond. Afterwards, Jill is appointed the new boss by her father, and they drive away. These events were, apparently, meant to prompt a sequel, but due to the game's unsuccessful sales, it seems unlikely.
The Red Dozers' Trailer serves as the Drill Dozer's "main menu". Here the player can save his or her progress, examine Jill's Drill Dozer's equipment, check the treasure he or she has accumulated, or visit shopkeeper's shop purchase energy tanks, drill bit upgrades, and maps to access chips. The shop is available after the first area, Skullker Factory, is beaten.
Drill Dozer is an action platformer in which the player controls Jill and her Drill Dozer. All seventeen massive stages are flooded with enemies, obstacles, and puzzles which force Jill to use Drill Dozer's drill in a wide variety of ways. The drill is activated by simply pushing one of the shoulder buttons. The R button spins the drill forward and the L button spins it backwards.
Scattered throughout the stage are red boxes marked with yellow wrenches that contain either chips or health. Each stage also contains two red gears that allow Jill to shift her Drill Dozer to the second and third gears. The higher the gear, the more powerful the Drill Dozer's drill is and the longer it spins.
At the end of each stage (with the exception of the secret stages), Jill must face off against an enormous boss and use her drill to exploit and damage its weak point.
In each world, there is a mini-boss and a boss. All of the bosses can be defeated by using your drill in various ways. The only boss where the drill isn't used is in the final battle with Croog. Your Drill Dozer falls apart, and Jill's only method of attack (and defense at that) is her fists. This final battle is the only battle where the boss does not have a health meter, as only one successful hit is required to defeat him.
When Jill's Drill Dozer runs out of health, the player receives a game over. He or she can resume the game at the beginning of the room the Drill Dozer was destroyed in by paying the shopkeeper fifty chips.
Drill Dozer was nominated as GBA Game of the Year by Nintendo Power, as well as Overall Game of the Year, and Best New Character (Jill) and Best Platformer throughout all systems for 2006. Of these, it won GBA Game of the Year as "NP's Pick". It was also runner-up for GameSpot's Game Boy Advance Game of the Year.