Xardion tells the tale of three warring planets that are home to three distinct alien races. Their fighting is interrupted by the threat of invasion from a much more potent alien race. The three planets find that they are able to set aside their differences long enough to battle their shared menace.
The single player controls one of three characters: Triton, Panthera, and Alcedes. Each character has special attributes that help the team. For example, Panthera's relatively small size allows him to squeeze into spots where the other two characters can not travel. The players can gather a number of unique power-ups and weapons to aid them on their mission.
The gameplay is an action-packed adventure with fast-paced combat against hordes of enemies. Players must navigate through levels, fight enemies, and switch between characters as needed. Each character has its own strengths and weaknesses, requiring the player to adapt their strategy to succeed.