Counter strike: Source is the follow-up to the popular Counter-Strike 1.6 which was much graphically outdated thanks to it running on the HL1 Engine. Now CS has made its move to the Source engine and players can enjoy the added realistic physics and greatly done lighting. The same "run-and-gun" gameplay still resides with this game to give it it's signature flavor.
All-in-all CS:S is pretty much the same game that you came to know and love in the old installment, all of the maps made a comeback with a much needed graphical facelift along with the character models and all of the guns. Another point that make Source great is that Valve still sticks to it mission of making games that look great but you don't have to have a monster rig to run it. So Valve makes it easy to jump into the action.