Ok first off I don't know who anyone can compare counter-strike
to this game, they are in no way similar except they are a FPSs.
Deus Ex is quite possibly the best game ever made. No game is as innovative, well executed, well written, and plain old fun as this. This game never gets old no matter how much you play it. You can play anyway you want and your actions will affect the outcome of the storyline in dramatic ways. If you explore the game deeply it has a lot of cool hidden stuff. It gave birth to the whole good-guy-bad-guy meter a lot of games have today (Knights of the Old Republic, Fable, Elder Scrolls), but this game pwns them all. The beginning of the game drags a bit but if you get past the first 2 levels it picks up. The story line is deep and fun to follow also. What really makes this game shine is the nano-augumentation system on how you can upgrade your-self and really affect how you play. This game is not for everyone, if you want a pick up and play game you will hate this. If you love deep, engrossing games with countless hours of replay, you will not be let down.
Though System Shock 2 had this concept and was around before Deus Ex(one year before I think), it was not executed well and had many flaws.
If you haven't played Deus Ex you have no right to call yourself a gamer. Buy or download this game right now, just play it!