"Ghost in the Shell: Arise" was aired in 2015, but is set before the 1995 movie and the 2002 "Ghost in the Shell: Stand Alone Complex" TV series. It's about the formation of Section 9, or at least Section 9 as we knew it in the movies and GitS:SAC. Everyone looks younger: this makes sense for Aramaki and Togusa (who are almost fully human), but not for anyone else as they're almost entirely cyborgs. By making them look younger, it implies they would deliberately age the appearance of their cyborg bodies - which seems improbable. My guess on seeing their appearance was that we were about 15 years prior to GitS:SAC, but I was way off: according to Wikipedia, "Arise" is set in 2027, GitS (the movie) is in 2029, and GitS:SAC is in 2030 (which makes NO sense, as Kusanagi pretty much left this mortal plane after the movie - not entirely ... it's a long story, but she wouldn't have been working with Section 9 anymore. However that's a failing of GitS:SAC, not "Arise"). And Aramaki's hair went from solid brown to solid white in two years??
We find out that Motoko Kusanagi never had a real body: her mother died while Kusanagi was still in the womb, and the only way to save her was to completely cyberize her at birth. And in the first episode she's still in the military because it owns her very expensive body. By the second episode she's gained both Aramaki's interest and her freedom, but she spends the whole thing fighting with a military unit that includes Batou, Borma, Saito, Ishikawa, and Paz. Prequels are BAD: in this case, they insist on condensing recruiting of "the team" to all come from one place (except Togusa from the local police), which seems extremely unlikely. Especially after they all tried to kill her. And let's not forget the Tachikomas - apparently so popular in GitS:SAC that they had to be re-incarnated as an earlier version, the Logicomas. They're only less annoying than the Tachikomas because they aren't called on to talk so much.
The most unfortunate change in character was Saito: in this series he swaps sides twice for money (do we really think the Major would hire him after that?), and he sleeps through everything, meetings and guard duty alike. This is very different than the character we see in GitS:SAC, who is both alert and reliable.
Kusanagi herself is an obnoxious bitch that no one would want to work for. In the movie and GitS:SAC she's a mystery, not terribly friendly, and she often does stuff unexpectedly, but she always has her reasons and it's clear why they follow her. Here ... she's just too distant, unpredictable and unpleasant.
The series consists of four one hour episodes: "Ghost Pain," "Ghost Whispers," "Ghost Tears," and "Ghost Stands Alone," followed by a particularly crappy two-part 50 minute episode: "Pyrophoric Cult," which is hardly more than a setup for the closing 100 minute episode "Ghost in the Shell: The New Movie" which - while not great - was possibly the best of the lot.
Overall not a particularly good series, but at least an interestingly different take on characters I like.