Mars Matrix is a top-down vertical scrolling shoot-em-up (shmup) game, originally for the Capcom CPS-2 arcade board. It is the second in a series of three Capcom/Takumi shmups, between Giga Wing and Giga Wing 2.
Mars Matrix features unique gameplay based on the "mosquito" system. By holding down the fire button, your ship can absorb shots and then "spit' them back at the enemies. Additionally, each destroyed enemy (and reflected shot) releases experience cubes of various values, which can multiplied by chaining. This experience is used to power-up your ship, and also acts as a multiplier for your score.
The Dreamcast port also includes some extra features that can be unlocked by accumulating points in the game. These features include replay videos, an image gallery, a score attack mode for perfecting individual levels, and even a complete extra game mode with a new enemy sequence.