Having read this I think I realized why I'm having trouble and so many other people aren't; I'm trying to play this game like it's normal D&D. I'm not picking up and throwing barrels, using jump a lot, stuff like that, whereas I feel like other people are using the game mechanics as given and are getting their heads around it faster.
Well, it's basically how it works. Just like in DOS 2, combat is like a puzzle. You have to be creative to solve it and destroy all the enemies.
But I don't know what kind of D&D you have played, because usually GMs reward creativity and inspiration in combat more than anything else.
Some people wonder why there are so many empty barrels for example. You can build literal walls with them and lure your opponents into the confined space you have created.
And so yeah, now I understand better why most players find the combat either easy or hard. I guess you can see who played DOS 2 and who didn't in their answers.