Dead Cells

This achievement is earned by killing yourself with an elevator. The earliest I was able to do this was the second stage - Promenade of the Condemned. Find an elevator, and use to fall through it. At the bottom, step on the button to summon the elevator down and then move directly underneath it. When it comes down on top of you, you'll take damage. If the first one doesn't kill you, will move the elevator up and you can fall through it, and hit the button again to repeat. As soon as the elevator delivers your killing blow you'll unlock it.