It's my personal opinion that games just don't have the same magic as they used to. It could be that we're breaching too close to reality with the looks, and realism effects and character models based on people we recognise might be taking things a little too far. Many games, particularly shooters have become a little tired and predictable.
I'm very glad to say that I don't find this to be the case with Gears of War. Made by the Unreal Tournament team, there was never a chance I wouldn't play the game, but I have been very impressed with this one. It features a relatively unique story (That's right, you're not technically human, and you're not technically fighting aliens), with brilliant gameplay, and some interesting mechanics.
GoW is an outstandingly beautiful game. I remember playing it through for the first time on co-op with my wingman, Parisienne XIII, and we came across the Fenix Estate for the first time. The only way to describe it is "destroyed beauty" (the name of the book that came with GoW2 LE). We were absolutely astounded at the visuals, and this isn't even talking HD, this was on a 28" 4:3 CRT (which sadly died halfway through out campaign, forcing me to upgrade to a 42" LCD HDTV, which made it all better).
The storyline is very well thought out, protecting your planet from invaders from beneath the ground, but what really makes the game is the gameplay and weapons. Epic have not stuck to the standard arsenal, instead changing things to be more challenging. You enemy; the Locust; are big, tough nasty enemies, and that's made your army get creative. You start off the game with your trust Lancer: a gun with a mounted chainsaw for a bayonet. Such a good weapon you'll never put it down, because it's just fun to cut the enemy in half.
Other weapons include grenades which you can 'tag' an enemy with, leaving them unable to do anything but try take you with them, and a sniper rifle which is an absolute pleasure to use. It's not your standard point and click, it requires skill, and aiming, and precision, because if you miss, it's only a single shot and you need to reload, leaving yourself open.
There are some game mechanics which have been added to the game which just help make it. The run is annoying as hell, giving you the chance to speed, but with no way to shoot while doing it. It does integrate perfectly however with the cover, which will let you stick to any solid object to protect yourself. It may be simple, but it's missing from so many games, and makes it so much more in depth. From there you have the chance to lean out and scope, blind fire, or just jump over and take 'em out John Rambo style.
My favorite mechanic however is the 'active reload'. When you hit reload, your character will automatically change magazine, however with the right timing you can hit reload again which will make your character get a perfect reload, speeding up mag-swap time, and giving you a damage boost. Not that it is all that simple a system. It's easy to do, but you are punished if you get the wrong timing, your character will fumble, and the gun will jam, taking more time than it would if you hadn't touched it.
The best part of the game for me however has to be the co-op story. The writers have obviously intended the game to be co-op and have written a great story revolving around both main characters. If you play single player, you will still always have your partner with you, but let's face it, co-op is just better.
With two of you, it means you get to plan tactics, operate ambushes, and above all, revive your friend when he gets bested, but it's not all fun-and-games. There are times when you'll need to investigate areas and you'll be split up to cover more ground. This tends to be when all hell breaks loose and you're out on your own, but it works so well for GoW.
I may be biased on the game, but it's one of my favorites, and I feel that it earned every part of that. It's well developed, gorgeous, and is actually fun to play. That's not always the criteria used for games anymore, and so I'll definitely take it when I see it.
Of course the game is quite slow-paced gameplay wise. If you want to be fast as jumping all over the place take CoD or Halo, but if you want a challenge, with a hint of brutality in it, Gears of War is your best bet.