Tom Clancy's Rainbow Six: Vegas 2

Summary pulled directly from Steam - Some text may only be applicable to Steam platform

Tom Clancy's Rainbow Six® Vegas 2 - the sequel to the award-winning next-generation first-person shooter - returns to Sin City. Tom Clancy's Rainbow Six Vegas 2 is your last chance to rescue America's sexiest city from an escalating terrorist siege that will force you into heart-pounding action from beginning to end. The best are back and this time winner takes all.
Recipient of numerous awards, including 2006 Best First Person Shooter and Best Online Game, Tom Clancy's Rainbow Six Vegas 2 pushes the top-selling franchise to new heights with new gameplay features.

Ubisoft Montreal Returns - Rainbow Six Vegas 2 is back in the hands of Ubisoft's Montreal studio, creators of the award-winning and highly acclaimed Rainbow Six Vegas, to ensure that ending to the Vegas story is one you'll never forget.
More Vegas - Sin City is back and bigger than before. Explore all new Vegas hot spots as the environment changes from dusk to bright daylight to dawn, creating a visual experience that is as challenging as it is breathtaking.
Improved AI - AI is more challenging than ever. Now, the terrorists are equipped with thermal vision, night vision, and shields - not to mention a multitude of varying reactions - all of which are guaranteed to give you a new playing experience every time you go into battle. As you progress within the game, you'll only be able to outsmart your enemies by taking advantage of intel opportunities, such as thermal scanning, and tactical strategies, such as leapfrogging.
New Weapons and Armor - Take down the terrorists more effectively using 11 new weapons. New camouflage, clothing and gear allow you to take customization to the next level.