Rebel Entertainment is coming out of stealth today as a new game publisher with a popular browser-based dungeon-crawling game on Facebook.

Burbank, Calif.-based Rebel, a division of Internet giant IAC, has been testing Dungeon Rampage for months, and it has garnered more than 2 million registered users during that time (and now 700,000 monthly active users). It’s a cartoon-like fantasy dungeon-crawling game, sort of like Blizzard’s Diablo III title but a lot less serious, Rebel general manager Mike Goslin told GamesBeat.

The title is unique as a fast-action, synchronous game in which players fight alongside each other in real-time, Goslin said. Most Facebook titles are slower games in which players take their turns one at a time. And while Dungeon Rampage is light-hearted and full of humor, it’s going after more serious gamers than your typical Facebook FarmVille game.

Goslin said he knows that moving into Facebook will bring the company into competition with established leaders such as Zynga in casual games and Kixeye in serious hardcore games. But he said that the company’s first title delivers a fast-action fighting game that you wouldn’t otherwise find on Facebook.

“Our game play is a lot more like an arcade title,” Goslin said. “It’s easy to play, but hard to master.”

Rebel is funded completely by IAC. Previously, IAC launched InstantAction, a web game publisher that it shut down a while ago. Dungeon Rampage will officially launch later this year on multiple platforms. Goslin said the company will add more features, heroes, maps, and weapons.

“We are going out as fast as we can to get up and running,” Goslin said.

Rebel was founded in 2011. The team comes from companies such as Atari, Disney, Insomniac, EA, and Zynga. It’s working on a number of different games. With Dungeon Rampage, players choose from six different warriors, like a hammer-wielding Berserker, a Battle Chef, and a katana-slashing Ghost Samurai. As the player, you explore dungeons, avoid traps, and kill monsters. The Flash-based browser game uses a two-dimensional, isometric view of the action.

GamesBeat 2012 is VentureBeat’s fourth annual conference on disruption in the video game market. This year we’re calling on speakers from the hottest mobile, social, PC, and console companies to debate new ways to stay on pace with changing consumer tastes and platforms. Join 500+ execs, investors, analysts, entrepreneurs, and press as we explore the gaming industry’s latest trends and newest monetization opportunities. The event takes place July 10-11 in San Francisco, and you can get your tickets here.