It aims to draw the player into combat, into a kind of exchange of deadly blows. It was designed to add to the emphasis that every encounter is a life-or-death situation.
When you take a hit, you lose a portion of your health bar. You have a limited time afterwards to regain that health back. Within that limited time, if you get your hit in on the enemy, you get your health back.
While it sounds like a highly offensive game, it's kind of like having a sword and shield, says the game's producer. While you have the opportunity to gain your health back, you have to determine at every encounter if you want to go for getting your health back. The situation, like number of enemies or location, and your equipment load out, will determine how successful you'll be in a Regain attempt.
We watched an example of the Regain System in action. A yellow trail shows on the bar after taking damage, but it quickly disappears. The goal is to hit the enemy back before it disappears to regain health. If you get hit multiple times you'll lose your opportunity to regain health, so you'll have to be careful as hits will have that yellow trail depleting much faster. Basically, if you take a hit, hit back quickly and cleanly, and don't get hit again before that.
A mist effect appears around the character to confirm that health has been regained.
can cause it. You can fix it by adding *.disqus.com to your whitelists.