Bullet might not be as well aimed as expected, considering some of the firing squad have blanks, and most of them probably don’t really want to be there.
Beheadings are reported to result in animated heads… and I would assume something like a waterfall of pain as the nerves from the body are severed but the brain, where consciousness lives, goes on for a bit yet. It might be quick, but it doesn’t seem pleasant.
Electric chairs, just look them up, same with lethal injection problems… any “justice death” is basically torture.
At least they can’t fuck up neutral gas asphyxiation. It’s either deadly or you sleep through it and wake up with a nasty headache.