These are the (possibly) frequently asked questions.
This be updated over time.

1. What does this do?
Did you even attempt to read the description?

2. What exactly does this do?
That is a little more complicated and will be covered in a discussion I will make.

3. Is this compatible with (mod)?
Compatibility is almost guaranteed. If you encounter a rare case where this mod is not compatible with something else, let me know.
The only currently known mods that are incompatible with Difficulty Overhaul are Difficulty+ (including Nightmare Edition and any add-ons for either).

4. Why don’t you just increase the health (and/or damage) of monsters/NPCs and keep everything else the same?
Have you ever played any of the Elderscrolls games, Fallout 3, Fallout New Vegas, or Fallout 4? When you increase the difficulty in one of those games, it does just that. It doesn’t make the game harder, it just makes combat take longer, causing it to become tedious and boring. This is exactly what I’m trying to avoid with Difficulty Overhaul, just as I did with D+ and D+NE.

4.b. Will you make a mod or add-on to this mod that increases monster (and/or NPC) health to (insert stupid proportion here)?
No.

5. Why make a new add-on rather than just update Difficulty+
I’ve considered simply releasing this as an update to the Difficulty+ series, but there are a lot of reasons why I didn’t. While Difficulty Overhaul patches the same files, and has the same objectives as Difficulty+, it has a different perspective on what the numbers mean and how they interact with each other which results in a different “feel” in gameplay making it a very different mod. While I prefer Difficulty Overhaul, I’m not releasing it in anticipation that everyone else shares that feeling. Doing this lets you pick and choose which one you like the most.

5.b. Are you dropping support for Difficulty+?
Yes and no. If a Starbound update breaks Difficulty+, I’ll get around to releasing an update to fix it. I will not be releasing any new add-ons for it.

6. Is this mod server-side or client-side?
Both. One of the files that Difficulty Overhaul changes is saved to the character upon creation (which is also the same reason why you need a new character). At the same time, despite being a small mod, Difficulty Overhaul changes almost everything in Starbound.

7. Why does this require a new character?
Difficulty Overhaul patches the file ‘player.config’, which contains information that is stored to a character’s save file. Rather than load the constants that are consistent between all characters when the game starts (that are contained in this file), Starbound is programmed to load them from the save file (this is something I found out while making D+ Nightmare Edition). While I am not going to pretend to know the reasoning behind this decision, it is a poor one from my perspective.

8. Can I get a non-steam link?
https://community.playstarbound.com/resources/difficulty-overhaul-plus-and-nightmare-edition.4983/