I personally don't care for the arguments about identity politics or strong female leads that seem to infest every discussion about this film. Helm's daughter is at the root of the conflict so obviously she's going to be a bigger presence when the story is blown up to a feature length. She's absolutely central to the film, if that's a problem then there's no getting away from it.
None of the fights felt especially epic. The biggest fight looked like 20 riders facing off against 50 homeless-looking guys with 3 elephants. There is nothing like the OG Helms Deep or Pelennor Fields here. It doesn't help that said fight is at night-time, meaning I struggled to see much of anything going on. Felt very much like the Battle of Winterfell. Other major fight scenes were completely buried under snow effects.
It's an animated film and there's a fair amount of backflips, super-jumps and general anime fan antics. Plus the obligatory Legolas-from-Temu where a guy takes a Mumak solo.
In fact there's a lot of scenes that felt awfully like a budget homage to the originals. Helm has some dialogue that is uncomfortably close to Theoden during the Ride of the Rohirrim and the super siege weapon feels like Grond if they bought it from Wish, since it was apparently destroyed by a single defender throwing a single fire bomb without much trouble.
I don't really understand why the Watcher was there, especially since everyone seemed to know it was there. I found its attack against the Mumak unintentionally hilarious. I also don't really understand why Hera was kidnapped only to immediately escape. There's a lot of scenes that felt either unnecessary or actively harmful to the story.
I like how the Snow Troll seemed to be a big thing in the GW previews considered it is completely obliterated about 3 minutes after it's introduced. It had a shorter shelf life than Smaug in BoFA.
Seeing Saruman was fun, but seeing Christopher Lee in the credits was ghoulish. I assume AI is to blame here. Again it comes back to blatantly riding on the coat tails of the original films to try and hook you with nostalgia.

My favourite dialogue was between Hera and Helm: "You can't pull apart his army one man at a time."
"Mmm, I can try."

Apparently Cineworld think a medium popcorn should cost £6.80 now. Peter Jackson was also gracious enough to pay for 40% of our tickets which took some of the sting out of it. Fortunately there were maybe 10 other people in the room so we didn't have to worry about distractions.

As for "girl power" I'd be far more concerned with her father's constant "Chuck Norris" meme antics. At least Hera can say she naturally inherit's his supernatural power, but its never explained where Helm himself get's his Incredible Hulk-like powers. Is he supposed to be a living demi-god or something?

When he finally dies I nearly yelled out "Oh please! Do shut up!", as it really looked like an Old Spice sketch.

The most Hera does in the film is defeat Wulf with a shield slammed into his throat. Its at least far more believeable than that girl from Prey besting the Predator in melee combat.

The Christopher Lee dialogue was taken from recorded line readings from The Hobbit. He had always said he wanted to do more Middle-Earth movies so his family gave them permission to include him within this movie.

"UP YOURS PENDRAGON!!!"

Frealaf not being the one to kill Wulf is the biggest actual change to the events as described in the books. I think it's acceptable because Frealaf is shown as being courageous, noble and smart in every scene he is in. You definitely get the idea he's going to be a great king, and that he's probably the better choice for king over Hera. Being able to kill a guy isn't the most important trait in a king, and I think Helm failing despite being an unstoppable killing machine reinforces that.

The Watcher in the Water scene I would cut entirely. You could do the same damn thing with just leading the elephant into a bog, no need for the bog to have a monster in it. I think it's taking liberties a bit too far - the Watcher in the Water being a "known" thing is not really in line with the text of the books. Also, the scene was really goofy, poorly animated and had poor design for the Watcher. It's probably one of the weakest scenes in the film.

Likewise Helm's battle to the death is cool, but the scene where he's frozen in place on the causeway afterward lands on the goofy side. It looked like a rush job, taking a still frame of him and applying ice effects to it, and didn't work. He also seemed to manifest his hammer out of nowhere, and he's frozen brandishing it and screaming like he was flash frozen which is...just a weird choice. I think the slow pan and voice over is crazy here and if I'd made something like that I wouldn't want much focus on it.

I thought the Battle of Edoras overall worked well. I thought it was cool to see the Mumakil in a smaller battle like living siege engines. More budget would have made it even better but it was alright.

Hera's outfit was really weird. No one else in Rohan looks or dresses like her. It wasn't like it was really revealing or something, but it was just really not the style of anything else in the whole film. I'd have liked it way more if she was just in the clothes she wore in the first scene instead, or just some basic chainmail or whatever. I didn't find her too annoying although she is obviously an insert and is obviously supposed to be bad ass. That's fine. She's not obnoxious, she listens to others and only argues with her dad that she could be a messanger because she's a fast rider - reasonable I think. She's brave and kind and smart, and I think it's nice that a little girl watching that might be excited or inspired by her. Helm is still an unstoppable superman by comparison, both of her brothers are shown in a purely positive light and are both very brave (one is more competent than the other but it's not shown in a humiliating way, more like it's not great that an artist is sent to war). Frealaf likewise is very brave and competent and every statement he makes is correct - if Helm had listened to him at a critical point they would have had no issues at all.

Olwyn is another insert but a really fun one. Combat Nanny is actually a very fun character and she's kinda understated and wry in a fun way. The whole "shieldmaidens" bit was a bit overdone but it only comes up a few times and I'm willing to forgive it. But it's probably the script change that I dislike the most - I think just having it be possible that there are shieldmaidens without there being a legendary order of shieldmaidens is better.

I liked that General Targ is not too bad a guy and is broadly pretty sensible. I thought overall that the film had a fair bit of humanity and decency in that way, and got across some of the moral messages I associate with Tolkien really well.

There are also some beautiful homages to the Jackson films in some of the still backgrounds, and I think that was nicely done. Shame the animation happening against those backgrounds doesn't live up to the same standard.

If you like the Jackson films I think there are far more egregious changes to the source material there than anywhere in this story, aided by the fact that the source material is so sparse here so there's more wiggle room. Stuff like "Go home Sam", Faramir talking the Hobbits to Osgilliath, the treatment of Denethor and Theoden, Aragorn beheading the Mouth of Sauron, Elves at Helm's Deep, the Army of the Dead at Pelennor and the character assassination of Frodo are much worse especially when taken together than the addition of Hera to this story imo.