If you had to spend 1 movement to climb a ladder to get range in order to use the knockdown, then you're down to +1. For example, if you use a knockdown arrow to knock down one of the enemies, that is +2 for you in action economy terms (along with a little damage) because the enemy loses 4 AP from not doing anything and you spend 2 AP (+4 - 2 = +2).

Thinking of the game this way, abilities can all be measured in their AP efficiency. That means that, on average, the team that takes the most productive actions is going to win the fight. The winner of the fight is usually the team that makes the best use of the AP economy. AP stands for Action Points, the little green dots you get at the start of your turn that determine how much stuff you can do on your turn. If you're interested in changing your build to better slay the wretched villains and the unworthy, let's get into it. I don't want anyone to read this guide with the mindset of 'I really hope this random guy on the internet approves of the build I'm using and love.' If that's your mindset, just keep using the build you love, you already love it! The guide is long, so feel free to focus on the parts that are interesting to you.

By necessity, any guide that recommends one course of action recommends against all other courses of action (even if many of those possible builds are quite enjoyable to play around with). I don't recommend reading this if you're just starting the game for a few reasons: (1) most of it won't make sense without the context of knowing a good bit about the game (2) it's fun to figure things out for yourself, and (3) playing a game with a goal other than trying to build the most powerful party possible is an excellent experience. This guide is 100% focused on how to fight things better, how to think about winning difficult fights, and how to build your character to deal truly divine damage. The combat in Divinity can be difficult if you don't approach it with the right strategy. If you're having trouble with Divinity 2, I've got quite a bit of experience and am hoping this guide will be helpful for you.

Divinity original sin 2 increase ap