(CNN) -- Gamers rejoiced over news that Blizzard Entertainment, the company behind popular role-playing game "World of Warcraft," plans to release its first new franchise in 17 years.

"Overwatch" is a team-based shooter game for computers set in a cartoonish version of the not-so-distant future in which a reformed band of heroes battles evil across the planet.

Blizzard, which has built a global fanbase through its Warcraft, Starcraft and Diablo franchises, debuted "Overwatch" Friday in a cinematic-style trailer at BlizzCon 2014, the company's fan convention, this weekend at California's Anaheim Convention Center.

The trailer was followed by a gameplay demonstration showing characters such as an armed gorilla and a pistol-wielding Reaper showing off their abilities.

A beta version of "Overwatch" will be available to the public in 2015, game director Jeff Kaplan told the crowd.

The game marks Blizzard's first foray into the multiplayer shooter genre and its first new franchise in 17 years. It comes on the heels of "Heartstone," a World of Warcraft-inspired card game, and "Heroes of the Storm," which features characters from other Blizzard games.

"Perhaps the most amazing thing about Overwatch is the fact that it was kept a total secret, a rarity in this industry," Paul Tassi wrote for Forbes. "Many were guessing that Blizzard's big surprise was going to be a new Hearthstone expansion or something along those lines."

Immediate reaction to the announcement was mostly positive, though some wondered if Blizzard should just stick to its tried-and-true franchises. Some fans noted references and allusions to weapons and characters from other Blizzard games.