Armored Core 4 is a newest installment in the Armored Core series of video games. It was unveiled in the Tokyo Game Show of fall 2005. Many people believed that Last Raven would be the last Armored Core game in the series, but a teaser movie shown at E3 earlier that year began to spark speculation. Codenamed "Project Force" the game shown at E3 bore striking similarities to previous Armored Core titles. At the Tokyo Game Show From Software later revealed that Project Force was indeed a next generation AC game now known as Armored Core 4. Armored Core 4 is presently being developed for both the PlayStation 3 and the Xbox 360. While developer From Software has previously created games for the Microsoft system, Armored Core 4 will be the first Armored Core game to appear on a Microsoft system. Sega of America has announced that the title will be shipped for both the Xbox 360 and PlayStation 3 in Spring 2007

Series producer and From Software CEO Naotoshi Zin noted in an interview with IGN that Armored Core 4 would feature multiple AC opponents and a reworked damage system that would be more "precise" than previous generation AC games. Players will also be able to customize every aspect of their Armored Core much in the way that the Gran Turismo series allows players to customize their racing cars for optimal performance. According to Zin Armored Core 4 would allow players to create their own 100% original AC. Armored Core 4 will be the first Armored Core game to be fully online, making use of the 360's Xbox Live and the PlayStation 3's online capabilities. Up to eight players can compete online in various multiplayer matches ranging from team battles to all-out battle royales. The game will not make use of the PS3's Sixaxis motion-sensing controller feature, however.

Armored Core 4 will have many new features, such as Spec Sheets, allowing players to trade AC configurations across the Playstation Network or Xbox Live. While the details for online on the Playstation Network have yet to be confirmed, FROM SOFTWARE has stated that the Xbox 360 version will have 8 player battles online, as well has voice chat.

^the xbox site is saying may'07 for asian version.