I think you are on to something Xeiom, it does really seem like there's an issue with the rules not being explained well.

Take modifiers and abilities. For instance having an odd number in an Ability is a bad idea. No one explains this to you, and the "suggested stats" and even party characters have poor stat distribution.

Same with advantage/disadvantage, and other to hit modifiers you might get don't really get explained well. So I can see I have a "green addition" to my to hit chance, and it states "backstab" but it doesn't say if this is advantage, or just a +1 to hit or anything. Especially "house rules" like elevation would be nice if the game told you what actually did.

But yeah, all in all the combat difficulty is quite decent once you learn the game. Sadly the prologue does a bad job of really teaching you the game rules.