In some sections in Witcher 2, the Quick Time Event (QTE) mechanism will be a gameplay element. It requires you to press the appropriate key when a hint is displayed on-screen. If the key hint is accompanied by a bar, it means you’ll have to hold the key until the bar is full. A failed QTE may have dire repercussions, so beware.
Witcher 2: QTE
From Orcz
