This topic is more suitable to answer this:
I would say, that there is no AI and decision making is terrible. For example, Firaxis’s XCOM isn’t military simulator, but the AI actively looks for cover while trying to flank your soldiers. Compare it to PP, where enemies are more likely to shot before move (or don’t move at all). They shot when it doesn’t make sense. Example? They could move like 5 tiles forward to completly flank a soldier but instead AI decide to stay in the open and put a burst that mostly hits poor cover. It doesn’t have to be milsim to make sense.
Difficulty if the game comes from features that are complementary to poor AI. Bullet sponges, pumping numbers of enemies (quantity over quality), metagame features like RF to punish you for shoting. This isn’t matter of semantic. The only thing this game provides over the games we already have is ballistic shoting system. Everything else is just bad (comparing with other games, as thats relatively bad, no bad bad per se)