Alright, I was waiting for this 1. First off, yes GoW did come from no where only to join mainstream gaming and begin kicking serious ass. However, the idea for the type of game is nothing original. The story line can be compared to many other games including Doom, Duke Nukem, and other such classic games where basically there are humans who get attacked by some monstrous force that causes them to hold out in some stronghold. However, what the GoW series really has going for it is its sometimes intense gameplay, wonderful co-op story gaming, for this I will quote...
"I'll be completely blunt, Gears of War 1 is perhaps the perfect co-op experience. The game just "got it" in so many ways. Drop in/drop out? Check. Integrated co-op into the story? Check. Online, LAN and Local Play? Check. Yes, Gears of War has it all in terms of co-op, and perhaps that is why it's the most popular cooperative game on our site. With Gears of War 2 finally coming out, we can only wonder...can it fill the big shoes created by it's older brother? I think the answer is a resounding yes."
---Nicholas "bapenguin" Puleo
And although from what I can think of now, GoW is the first series to have a third person "over-the shoulder" style of gamplay that was actually very effective and pleasurable to play with, yet it still is no where near the first game to do this, just the 1st 1 I can think of that really did it right.