grisan said:

Ziggy Stardust said:

grisan said:

(never understood why a few seconds of force lightning should kill him).

Because the lightning caused his breathing apparatus to malfunction.

I have read that explanation several times and it makes sense, but I still think it should have been mentioned better in the movies or the damage by the emporer shoudl have been made more obvious. That's why I listed it as one of my main flaws of ROTJ.

No. This is stupid prequel logic: "We need to explain everything!"

I never questioned that the full powers of an evil, powerful, sorcerer could kill even Darth Vader.

People forget the impact of that scene at the time - the lightning came out of nowhere. You were not expecting it. Force lightning was badass...until ruined by AOTC.