Fans of Valve’s inventive 2007 first-person puzzle game Portal can finally stop begging for a sequel. The developer announced today that Portal 2 is coming this holiday season.

The news follows a series of cryptic updates to the original Portal — including a new achievement and mysterious sound files, a collection of bizarre images, and a new ending (see video below) — which has had gamers in a frenzy over the past week. We still don’t know much about the sequel, but details will begin dropping this month. Game Informer announced that Portal 2 will be its cover story for April — the issue should feature a 12-page piece on the game, and will unveil new gameplay mechanics, story elements, and twists. The magazine will also drop further details at its Portal 2 hub throughout the month.

Portal was a fairy-tale success story for independent game developers. The game was a successor to an independent game called Narbacular Drop, which was developed by a group of students from the Digipen Institute of Technology. The students were hired by Valve and spent a little more than two years developing Portal.

In the game, players control a protagonist named Chell who must navigate her way through a variety of environments with her trusty portal gun. Her guide and tormentor throughout the game is an artificial intelligence called GlaDOS — who evokes classic villainous AIs (like HAL 9000) with a more comedic bent.

Portal was launched as part of The Orange Box — a collection of games released by Valve which included Half-Life 2 (and two of its expansion episodes), and Team Fortress 2. Despite being an unknown property (and a shorter game than any of its Orange Box companions), Portal went on to gather a massive cult following thanks to its unique gameplay, and its well-written and hilarious script. I’d argue that it was also the most enduring game from that collection as well.

Needless to say, the sequel is hotly anticipated. For now, check out the updated ending sequence to the original Portal, which hints at what may happen in Portal 2.