This is about as close to perfection as you're going to get....how can Gamespot only give this a 9?
The story is actually something rare in games nowadays - it's a very simple storyline. It doesn't try to be Final Fantasy with a long, drawn out story like almost every game now, it's short, simple and to the point. The cutscenes are not long at all (with the exception of the opening scene) so they never interrupt gameflow...great job rocksteady....I wish more action games would take note.
Gameplay is outstanding. There are 3 parts, combat, predator, and puzzle solving. At first, combat is easy and kinda boring. But as you keep playing you will discover new moves and it becomes addicting by the end. Predator mode is very original...you have 6 or 7 guys with guns and you have to stay in the shadows and take them down one by one. It takes patience. Sometimes you can spend up to 30 minutes figuring out how to kill everyone.
Challenge mode is a great add on imo. It adds lots of gameplay in addition to the story line. You have timed rounds in combat and predator modes, your goal is to beat your previous score and achieve certain challenges on each stage. It's a cool side game you can keep playing after you beat it. The only downfall is that it's pretty useless during the game, it only becomes fun after you beat the game.
You have to dig pretty deep to find flaws in Arkham Asylum. The only flaws I've found are in combat, sometimes in the middle of a combo Batman will not attack the person you want him to. And sometimes it's difficult to tell if Batman will kill an enemy or attack another one. But that's about it.
Overall, this game is so enjoyable, so challenging, and everything is paced perfectly. Nothing ever gets tedious or boring. Technically, it's one of the best games of this generation. It's not overly complicated but it's not too easy. It's as close to perfect and you're going to get.