A typical multiplayer beat'em-up in the tradition of "Golden Axe" and "Guardian Heroes". One or more players control small characters in a side-scrolling environent, defeating multiple enemies attacking from all sides, gradually advancing to the left or right depending on stage. Each stage ends with a boss fight. Characters have special moves and gain experience points as they move on; these experience points are used to "level up" the character. These levels are also saved in between gaming sessions, so the first stages will become easier and easier as your characters level up while the enemy doesn't.
From the XBLA description
A spinoff to the fightning game "Phantom Breaker, "Phantom Breaker: Battle Grounds" is a cooperatove action ame for up to four players. Cute versions of the series' characters dash around the screen in this action packed titles. Defeat ememies to raise your characters' leels and freely assign skills to your liking. Also enjoy head to head fights in the Battleground mode.