The story of the series is fine as its been seen many times but that just makes it slightly disappointing when it doesn't really do anything different with the setting apart from one factor later on in the story but they never develop it further. The series mainly focuses on character development through slice of life segments between the cast. Its more of a cute girls do cute things like Love Live than a battle action such as Madoka Magica.
I personally think a great example to compare this anime to is Yuki Yuna is a Hero as both are set in similar premises around protecting a town with a tree in it. If you watch both series you can also see what's holding Battle Girl High School back.
The BIGGEST glaring flaw with this series that really held it back for me was there's just WAAAAY too many characters. Seriously there's 19 main characters in total. My personal favourite was Miki and being the main character I hoped to see a lot of her. Sadly I was denied. The fact that there's so many characters they have to have screen time for all of them which makes 2/3 of the series just an episode that focuses on a particular three meaning your favourite character, if not one of the major ones will most likely only get one episode of actual importance. I personally think Love Live is a good example of the max amount of main characters a series can hold without being a big cluster. Also since there's so many characters reaction scenes are a pain since they need to show everyone's reaction to something and it takes a while and is ultimately pointless. Well the cast is basically a huge collection of types we always see in anime so you'll guaranteed to at least find one you like.
Another major disappointment for me and the reason I watched the series to begin with was character interactions and relationships. I'm a huge fan of female best friends being the main focus like in Yuki Yuna is a Hero with Yuna and Togo and Shoujo Kageki Revue Starlight with Karen and Hikari so I went into the series expecting a good amount of screen time to focus on the relationship between Miki and Misaki as it was hinted at the beginning of the series. They do have some time to have them together but again it comes back to the problem of too many characters in one series that's only 12 episodes.
However don't get me wrong it is a good series if you're not wanting a major story or character development and just want a relaxing anime to sit down to.
The character designs are nice especially some of the later costumes and there are many well known voice actors present that at least help try and distinguish characters apart. My personal favourite voice actor Yuki Aoi also being In it along with Hayami Saori.
The main enemy of the Hoshino class the Irousu are also very generic alien enemies you see in many series like Darling in the FranXX. They're never really explored which makes sense since they need so much screen time to develop their humongous cast. There is a plot twist later on with the villain but is very predictable from the start of the series so don't expect great villain either.
The power of friendship is also very prevalent throughout the series so if you're not a fan of that then this series isn't for you.
This review ended a bit on the negative side but overall Battle Girl High School is a good generic magical girl anime that's a good watch as long as you're not expecting much from it. If the series had less characters I really think it would have been much better as it doesn't give room for much to happen.
7/10 would only recommend if you're looking for a chill anime to not think too much about.
