The tactical shooter has so much to offer and Raven Shield is a perfect example..
So far as single player shooters go I've played this one more than any other, i've completed it about 3 times on different difficulties and even now I keep going back to it, Raven Shield has a suprising replayability value.
Having not played any rainbow six games previously I was a little dubious going into this one and to be fair its not terribly accessible, its hard, its hard six ways from Sunday but, and there is a but, its the sort of difficulty that you can master and learn to really enjoy.
The first time I played Raven shield I got about half way, lost half my men, got stuck and gave up; the second time I got about 2/3 of the way through losing one or two men got stuck and gave up; the third time I used the same squad of three guys through the entire game and the last time I played it I used just one man all the way thorough.
Raven shield is the sort of game that you play though and then come back to and find yourself setting challenges, like: i'm going to do this mission with just one man, or with just pistols, or just sniper rifles.
Raven shield pulls off a near pefect blend of variety, stealth, open maps, plot driven objectives, and suberb gun play.
Make no mistake, Raven Shield is hard core tactical FPS not for the faint of heart, only true FPS fans need apply. For the true FPS fan though, what we have here is game that you will keep coming back to for years and years.