Like other Lego games I have played, this one is a lot of fun, funny and the people working on it clearly know the source material very well. An example is the opening is the classic batman music from the animated series and the opening is similar to it with two random thugs on a roof top, batman jumps down, leers at them, they draw guns that get knocked out by his batarang before he beats them down and then poses ontop of a building with Robin joining him.
Almost every single batman villain is in this one. I can understand not including every single damn one, but they did a good job in getting many of them from the famous joker to the infamous Mad Hatter and reletively unknown, Killer Moth. As it's a Lego game all the characters are representing in a comical way and at times the characters act more like the 1960's batman TV show with Adam West, however at other times it's more like the show where in the sewers a Crocodile jumps up, Batman leers at it and then it runs away because Batman, he's the man.
I also enjoyed playing the villain side, doing the stuff before Batman arrives on scene and doing the freeplay missions are quite fun. Most things are obvious to find hidden, but others are so damn well hidden it takes a while. Thank god for guides on the internet.
Overall, I'd say go for it. It's a lot of fun and is one of those perfect games to play to cut off the edge of the day and can get very addictive too. Like all Lego games it's easy and this one has adaptive difficulty too. I can't wait to play the second one as that one is meant to have the DC heroes in it too, though for some reason it's still called LEGO Batman 2, perhaps it takes place in Gotham and is focued on Batman? I'll have to wait and see.