VERY intense.
For starters, this is clearly one of the best looking games I have ever played. I can't think of a better looking game. Everything about the characters and the environment are just immensely detailed and really bring a sense that you're in a living, breathing world. The graphics alone are a huge achievement.
Arguably more brilliant than the graphics is the gameplay, which again is unlike anything I've ever played before. There's a REALLY deep cover system where you're always taking cover and hiding behind a slab of concrete or a wall, poking out for a few shots before retreating again. It works really well and helps to distinguish Gears from other shooters out there.
Gears also features an intense online mode that can be alot of fun to play. The only problem I found with this online mode is that the only people who still play it are the experts, and so for a newbie to play and try to get good at it, it can be frustrating since there's no one of your own skill level and so you're forced to play against experts... to be honest, it's because of this that although I play the online mode for a couple of hours here and there, I can't seriously get into it.
In terms of the single player campaign, it's very thrilling and very satisfying. Whether it's the characters or the fights or just anything really, it's all crafted together so nicely. Some people thought that they went a little too light on the story, just using it as a means of giving a sense of direction in going from point A to B, but I somewhat disagree. While the story isn't as fleshed out as it could have been, it does a good job of keeping you wondering what's going to happen next, and I thought that the story as a whole was nicely done. The ending was exciting, though it did admittedly feel a little rushed. Still, the story did a good job of keeping me anticipating Gears of War 2 and wanting to know what will happen next.
So overall, Gears of War is a great game that should not be missed! It's not only the best looking game, but it's also got some of the best shooter gameplay so far this gen. While there are some things keeping it from being perfect, it's definitely up there with the some of the best games. Here's hope Gears of War 2 is just as amazing.