CS:GO feels like what CS:S should have been. In some ways feels a bit like L4D2/Portal 2 since it's on the same updated source engine but that's almost purely aesthetics, the hitbox/movement speed/maps are all vastly improved from what CS:S was. It's still very fast paced, and requires tons of skill to play well. There's some new gear included like molotov cocktails and tazers that 1-hit-kill, but it also includes by default several new game modes that're old to the CS scene that used to be mods (like gungame). Beyond that, the maps themselves have been changed drastically. There's new ladders and stairs in places there weren't any before, likewise I've encountered several bugs by dropping the bomb in places that it can't be reached, and sometimes being able to go out of bounds. You can play matches with friends without buying a server now as well, it has p2p gameplay, and you can host dedicated servers, but at the moment you can't seem to host a private p2p match, and like most CS games it has LAN support as well. So there's still lots of things that still need fixed/patched in the beta before the full release, but according to Valve they plan to do that by Friday, and give it some final testing before the 'Pre-Order' beta starts on the 14th. Either way, it's super fun. I hope some of my friends pick it up so I can play some with them, either that or I might buy a few gift copies.