The "purists" really don't like "Gotham."
That's too bad, in my opinion, because this is a pretty good show with some interesting plot devices, some nice special effects, and some refreshingly new interpretations of longtime characters from the comic books about the Caped Crusader.
Before I get into that, however, a few words for the "purists."
Batman has undergone many, many changes over the years. Those who read the first issues - say from 1939 through 1950 - wouldn't recognize the Batman from the Fifties and early Sixties and those who read the comic books about The World's Greatest Detective during those years certainly would not recognize the campy Caped Crusader of the late Sixties and Seventies. My point is that there is NO one version of Batman. The character has changed repeatedly from the days when Bob Kane and Bill Finger first started drawing and writing him. At various times over his long history he has been in alternate universes, fathered children with two different women (neither of whom he was married to), his appearance has changed (often), he once had a crime-fighting canine, for a while he even had a partner who was an inter-dimensional imp that idolized him, and... well, you get the point.
That said, I personally do not see why some people hate this retelling of the early days when Jim Gordon was a young detective trying to clean up Gotham's crime-ridden streets. Frankly, I think some of the casting and writing is inspired. Having Sean Pertwee play Alfred, for example, as a tough former Royal Marine who helps train young Bruce Wayne is brilliant. Without his guidance and training, we are forced to believe that Bruce - a privileged son of wealth with no background in martial arts - magically transforms into a street-smart guy who can more than hold his own in a fight with some truly vicious people. That lack of early training is such a huge hole in the Batman canon that Christopher Nolan's film trilogy has him disappear for a few years to be trained in how to be a fighter in a far-off land. Simpler, by far, to have Alfred begin his training AND instill in him the need to temper his thirst for revenge with the need for justice.
(As an aside, this is not the first time Alfred has been portrayed as a badass. In the "Earth One" graphic novels, he is the head of security for Wayne Enterprises so the "Gotham" version of the butler who raises young Bruce Wayne is not without precedent.)
Similarly, I like the casting of Camren Bicondova as the young Selina Kyle because she bears a striking resemblance to Michelle Pfeiffer, the best of all the women who've ever played Catwoman.
One of the major criticisms of the series seems to be that the stories tend to be over the top in many instances.
Is that actually a problem?
The reason: Come on guys, these are stories about comic book heroes and villains. They are SUPPOSED to be over the top. If they weren't, "Gotham" would be just another in a long, long line of police procedural dramas and Lord only knows we've got more than enough of them already.
I could go on but this series has already been reviewed a thousand times (at least) so I won't. Suffice it to see it is, in my opinion, worth 4.5 stars and I hope it lasts a few years because I very much enjoy it.