Following on from last night’s reveal by Epic Games’ Cliff Blezsinksi on the Late Night Show with Jimmy Fallon, Microsoft has released a few more details about Gears of War 3, including a haunting debut trailer for the game and the first screenshots.

Gears of War 3, dubbed by the publisher to be the “biggest blockbuster game of 2011,” will be the “explosive finale to the landmark Gears of War trilogy” and will be available exclusively on the Xbox 360 in April 2011.

Microsoft took the opportunity to throw a lot of descriptive phrases into the press release, including “spectacular conclusion to one of the game industry’s most memorable and celebrated sagas” and “epic story finale” to “one of the biggest franchises in Xbox history.”

Of course with over 12 million units of the games sold worldwide as well as toys, collectibles, apparel and an upcoming film, graphic novels and a book series, you can hardly blame them for choosing to blow their own trumpet a little.

Gears fans can also look forward to new Avatar items which will be available on Avatar Marketplace on the 20th of April, including the new COG amour introduced in Gears of War 3.

Epic Games will once again be handling development duties on Gears of War 3, which “plunges players into a harrowing tale of hope, survival and brotherhood” to complete the current story arc for the series. The last human city has been destroyed and the last remaining survivors are stranded, leaving Marcus and his comrades in a race against the clock to save the human race from extinction.

Here’s what Cliff Bleszinski, Design Director at Epic Games, had to say: “When we released ‘Gears of War’ more than three years ago, we set out to tell the world an unforgettable story of bravery and sacrifice in the face of insurmountable odds, and a year from now, players will get the chance to experience the final chapter in the story of Marcus Fenix and his companions in Delta Squad. This is definitely the biggest and most dramatic chapter yet in the ‘Gears of War’ saga, and we can’t wait to deliver it.”

Watch the first trailer and ogle at the first screenshots for Gears of War 3 below. Titled ‘Ashes to Ashes,’ the trailer was created in Unreal Engine 3 by the same team behind the Gears of War video spots and captures a three-way battle between Delta Squad, the Locust Horde and the new Lambent.