The witcher 2, how does adrenaline works?
Solution 1:
The adrenaline bar is activated once you learn your first ability which requires/uses adrenaline.
Also see in the Witcher wiki: Adrenaline Rush
The three skill trees will give you different abilities which are activateable with X (in the case you play with a gamepad directional button up):
- Swordman skill tree: Instant Multi Kill of 3 enemies
- Magic skill tree: A field similar to Yrden
- Alchemy skill tree: More attack and defences
This answer is also interesting and provides a screenshot of the adrenaline bar: https://gaming.stackexchange.com/a/178593