The evil alliance under the leadership of Belser is attacking your world; as pilot of a Silver Hawk fighter, your goal is to stop them! Darius Twin is a side-scrolling shooter similar to other games in the Darius series. You'll fly through a series of different stages, each with numerous enemies and ending with a large boss.
You begin the game with a limited amount of firepower, but after shooting certain enemies, power-ups are left behind to increase your capabilities. Unlike many of the Darius games, if your ship is destroyed, you don't lose all of the weapons you've collected; likewise, you also continue on at the same point rather than being sent back to a checkpoint.
Similar to many of the Darius games, there are different routes that can be taken towards the final stage. At the end of each stage, you're shown a map and can select the next stage you'd like to complete.