What was the hardest thing you’ve ever done in a game?Watch
EDIT: Also, completing Final Fantasy 10 when it was modern. That was a slogfest!
Ironman world conquest in Europa Universalis 4 with patch 1.30.4. After several abandoned games where things didn't go right, the final game ran to over 40 hours.
The toughest one was any level I selected in the NES game Silver Surfer. Always failed to accomplish one level, just one! do you know this game anyway? don't mind, if you don't. The game is the epitome of frustration and insane difficulty.