Mine is probably the Liberty City Minute achievement for Grand Theft Auto IV. I think technically you have 30 hours to beat the main storyline but I managed to power through and beat the entire game in one sitting.
Achievements were only added in after an update a couple years ago (when they removed the dated Games For Windows Live DRM that made the game pretty much impossible to play without modding) so it’s technically not the rarest for the game. The achievements for getting the highscore in QUB3D and flying underneath the bridges are even more rare but I’d argue they’re easier to get.
What Steam achievement are you most proud of?
Is there one that took a lot of time to get? Did you have a good time with friends? Was it an achievement you struggled to get on other platforms when you were younger?
Regardless I’d be interested to hear about it.
The Hammered achievement for Divinity Original Sin 2 which you achieve by defeating an endgame boss in your first encounter with them in act 1. I used a very cheesy method where I chain teleported the boss and her minions on to a rock in the middle of the sea. And then my archer who was on a cliff type thing on the other side of the beach slowly shot them to death. It was very funny!
You can also stand on the wall next to the gate, block the access by ladders with flower pots, and teleport the removed up to you. She can still hit you, but nobody else can, so it’s still pretty cheesy XD