And the world record for "most botched execution" goes to...

[Philippus Flavius Homovallumus]

Punning aside, the death penalty is not necessary for public protection.

If you insist on doing so, the guillotine, long-drop hanging, and multiple live-round firing squads really do outstrip the others for brevity of suffering.

Killing someone is terrible - lethal injection is couched as a medical procedure, it's their to make it nicer for the state, not the sentenced.

Poleaxe or go home.