The Empire of Reimia (3)

otherwise, you'll just keep growing and growing, and in the end, you'll turn into a Hive creature and won't be able to defeat anyone.

It's also part of the intrigue, and in my opinion, it's better than immediately finding a powerful item in a dungeon that gives a huge bonus to stats, and then being instantly half-defeated by a slime and becoming unable to fight.
Here, it's more gradual; through pain and hardship, you develop your character... Or you don't.

Even though the game ended prematurely for the umpteenth time, I'd say it should be considered both finished and successful.

I agree; the game was quite long, and I was already very worried that sleep mode or some other misfortune would prevent Revan from continuing, and everything would just hang in the air. But he did a great job and brought it to a critically important point for the narrative, and then it continued on autopilot... Which is fine, I guess.
Although I'm a little sad that I didn't personally participate in all these military operations, didn't try to save more people from the school, didn't shed a tear over the best teacher in the world, Muscari (I'll cry in my own epilogue), but still, it turned out to be a good story.

apart from the combat, it's not only difficult for the player to grasp, but it also seems to have been too time-consuming for the GM.

Yes, it took me a long time to understand how the attack line and other things actually work. I may not have fully understood the more subtle aspects.
And in my opinion, there were imbalances. For example, despite the interesting defensive options (mines, barricades, etc.), the inability to set them up before a battle made them useless in most situations, especially for players.
The right to the first turn, combined with orders and tactics from commanders, made the first turn incredibly overpowered.
On the other hand, if you fix this as in the last battle, with snipers intercepting spam units and heavy weather conditions, the situation becomes reversed – it's only possible to counter the enemy by randomly guessing.
Nevertheless, this combat system is the one in which I first saw well-implemented firearms and military equipment. I first saw rear attacks and tactics based on them in this campaign. The very idea of commanders, who really change the course of the battle instead of just giving stat bonuses, looked great. I was really into all of this, because it was something new and clearly different from ordinary fantasy campaigns.