As I understand it, you slowly fill up your critical meter with every attack, with a luck based multiplier. What I don't understand though is how you "execute critical", do you have to be in vats? Would be lovely if someone could explain

Outside of vats you can still get random crits and firing shots inside of vats builds up the critical meter.

There are also some perks, like Gun Fu, that give guaranteed crits.

Actually, I'm eager to see Nukapedia and the Vault getting udated on perks, because of how random perks and crit creates a lots of questions to ask about timing, just to know if one can use it's VATS bar without loosing a lots of things or if one have to gets out of VATS almost after each shot to get the most of his perks.

I've got questions around this too. Do headshots simply do more damage inherently, or are they near-guaranteed crits, as in prior fallouts? I know they do more damage than normal shots, but via what mechanism?

What does non-vats crit rate look like?

Is it possible to crit in VATS if not spending the crit bar?

Do any weapons have different crit rates?

There are a lot of combat mechanic questions we should get a handle on in order to best optimize our builds and how we approach combat...