Deadpool
50 Achievements
1,000
15-20h
Game Over!
Stealth Killed Sinister, in the Prison, with the Sword! Details for this achievement will be revealed once unlocked
20
How to unlock the Game Over! achievement in Deadpool - Definitive Guide
You get this just before getting the Game On! trophy but it doesn't matter what weapon you have before killing sinister, as the cutscene is always the same and Deadpool always uses the sword.
At the end of the "Landed in Prison" level, you'll be in the room with Sinister sitting on a throne and some enemies around. Stealth kill all the enemies to get to Sinister undetected, then stealth kill Sinister for this achievement to pop. This may actually be unmissable. If you alert the enemies on the approach, it reloads your checkpoint automatically. I'm not sure if you can kill him with anything other than the sword, but if not, you'll get this automatically.
At the end of the "Landed in Prison" level, you'll be in the room with Sinister sitting on a throne and some enemies around. Stealth kill all the enemies to get to Sinister undetected, then stealth kill Sinister for this achievement to unlock. This may actually be unmissable. If you alert the enemies on the approach, it reloads your checkpoint automatically. I'm not sure if you can kill him with anything other than the sword, but if not, you'll get this automatically.