It works like this:
- In all difficulty but easy, you have have basically no regen.
- In easy difficulty, a portion of your health regenerates (around half)
- The Vitality level 2 passive power (that we call Enhancements) allows a portion of your health bar to regenerates (in easy difficulty, it's added to the base regen).
This is mentionned in this (french, sorry) preview : http://www.jeuxvideo.com/articles/0001/00017132-dishonored-e3-2012-preview.htm where they explain some of the level 1 vs level 2 power effects.
Also, note that enemies inflict a LOT of damage in Dishonored, so even with the Vitality power, you can never be a tank, and you will definetly want to be able to heal yourself in combat with Elixirs.
So I tried to read the article as accurately as possible via Google Translate. I think I read something about an enhancement that lowers mana cost of the abilities. Can you please confirm if this is true or is my french+google's translations really that bad?
I would also like to know as what other interesting enhancements are there. I find Shadow Kill (or Ash we are not quite clear on the name yet) to be a really good enhancement that I will definitely get at least on one of my playthroughs. It not only sounds good but it gives you a lot of speed and momentum to the assassinations. And like makatak7 mentioned in one of his comments it would be really fun to stop time and assassinate one of two guards standing near one another. There where two guards in The Golden Cat level that where talking to each other. Imagine if you stopped time and assassinated one of them with the Shadow Kill enhancement. That would be so funny.
Guard A:So how's the wife and kids Joseph?
Guard B:Oh, you know?! Same old same old. You going to that party over at Garry's place tomorrow or do you have a shift again?
Guard A:Probably not. The twins want to go to a different party...HEY! Where did you go?