Perfection until it finished
Batman is a great game with a horribly out of character ending. The game starts with a good run through of part of the asylum to give the mood. And man does it do a good job. This game is dark and it lets you know it. I love the setting and tone that the game sets, and its pacing is consistent all the way through. After the initial opening scenes of the game, you go outside and all preconceptions of this game are shattered. The game opens up, and although you have a specific direction you have to go for the main quest, and there are no sidequests, there ARE riddler challenges. These range from the mundane (kill joker teeth) to the interesting (find hidden trophies) to the fantastic (answer a riddle by taking a picture in the environment).
The combat is great, the freeflow combat against other unarmed men can be frustrating at times if you attack, then realize an off camera man is about to hit you, but you can't counter in time. Overall though it looks good and feels good. The 'predator' type of rooms present you with a more stealthy element since the guns will kill you in seconds. You are human and you feel it. It is fun to watch the enemies slowly freak out as you pick off their buddies until the last guy is walking around randomly shooting at nothing while screaming for you to come out and face him. Extremely satisfying.
The story is interesting and is paced well, until the ending is reached. I'm not going to spoil anything, but the ending doesn't work for me. It's horrid. It put a bad taste in my mouth, but hey its only a very short time, and the rest of the game was so fantastic, that hard as it tried, the ending couldn't ruin the game for me.
Beyond the main quest (which i finished with 50% of the riddler challenges in 9 hours), there are also challenge rooms in both 'predator' and the freeflow combat types and get extremely difficult. Both are good and fun, but they are still simply add-ons to extend the "There are __ many hours in this game!". And that doesn't mean i want multiplayer, on the contrary, thank God there isn't multiplayer. It wouldn't have worked.
Overall, its not Bioshock, but its a very good Metroid style game in 3D, its fun, you should play it, and whether its a rent or buy is simply up to how many times you think you'll replay it. I rented it, finished it, and don't really plan on going back, but I did the same with Bioshock so it's up to you.