I also do not understand the very poor reviews, this is a very serviceable action movie that is certainly a step up from The Old Guard and Extraction.
Warning Spoilers....
This film actually does some things most films won't and is all the better for it.
Firstly, we don't find out the tech specs of Leo, we have no idea what he can and can't do, if he's a walking tank like a terminator or as fragile as glass, these elements don't get answered till later in the film, and even then only in part. So when we see that characters in a conflict zone, shot at, held at gunpoint, we are still invested, as we don't understand the mortality of the character. Much like Highlander and other older movies, it understands that the audience don't need huge exposition dumps on everything in Act 1, and mystery is often better than any explanation the scriptwriters could come up with.
The moral of the story is basically 'What is acceptable collateral to end a conflict?' and it plays on this fairly well, the idea of a human who makes cold calculated decisions, being put in an environment with robots and A.I making those same decisions, forces the soldier to develop his humanity. Its hardly a narrative masterpiece, but it's nice to see a film where the characters have a genuine arc through the film, as apposed to almost no character development in favour of sequel set up.
One thing many have said is the idea of why Leo, the most advanced A.I created is in a store room in the middle of a conflict, and that this is some kind of plot hole. Again this is a element the film doesn't explain, but I like to think it's because he is basically a failed experiment, but too much of a financial investment to waste. They wanted to create a loyal advanced A.I soldier, but the soon realised he was far too objective and independent to simple follow orders blindly, and so was banished to admin and milk runs. And since then has been trying to figure a way out of his situation. Again the how and why of how Leo ended up there is up to the audience.
Dont get me wrong, the film has its weaknesses, the script feels like it's a little undercooked, with the odd cheap marvel quote dropped in. The ending is very cliche and a little bit too Micheal Bay for its own good. The acting is 'fine' again in a story based around robots and almost sociopathic humans, getting a performance with any emotional range is pretty much muted by the nature of the characters themselves.
But this film is actually a lot stronger and little bit smarter than it has any right to be. And reminded me a lot of 80's standalone action/sci-fi movies. It's not trying to be intellectual, it's not trying to weave to complex narrative of characters, with a deep hard hitting morality.
It's an action movie with a original take on the AI/Cyborg story. It doesn't offload tons of exposition or hammer home a message, which means you can actually discuss the film afterwards, expand and explore the universe in your own way, and fill in some of the narritive blanks yourself.
In short, it's a enjoyable action movie, with some great moments, a good cast and great production design, and a well paced narrative.
Go into in with the mindset of watching something like Highlander, Fortress or Commando, and you'll have a good time.