The best thing I can say about "Gamer" is...this wasn't the worst movie ever, in fact, it wasn't even all that bad. That said, this isn't a great movie either, and I sort of feel like I've seen this type of movie done over and over again.
"Gamer" is set in the future, but not too far in the future. In this world, a genius has created a way for people to play simulation type video games using other people as their avatars. Initially, the concept was for a Sims type of game, where your real person avatar lives out what you control them to do. Then, this concept was take 1 step further with a live, first person shooter game using Death Row inmates as the avatars. The hero of the film is John Tillman (Gerard Butler), or Kable, who is just a handful of games away from earning a full pardon for his crimes. The gamer who "plays" as Kable is a 17 year old kid. But, as Kable gets closer to his release, it becomes clear that he'll never be let out the game without a fight.
Like I said earlier, it wasn't bad, but it also wasn't great. Actually, my favorite thing about the movie was the, somewhat, all-star cast. Lots of top notch TV actors, and several 2nd Tier Hollywood stars show up in this movie. The action is good, but the plot is nearly non-existent. It's a lot like the recent G.I. Joe movie, in that things happen, but nobody really reacts.
"Gamer" is a 3 star movie, and definitely earns its R rating. I wouldn't recommend this to anyone who isn't either a video game fanatic, or an action junkie.