What was the hardest game you ever played?

[Jaden1291 the Toad]

So far, the hardest game I ever played was Geometry Dash. Yes, Geometry Dash. The demon-rated levels (that's the hard ones) can throw me off-course with its timings, synchronization, and ways of flying, and I have to start over from the beginning of the level everytime I crash.

I would consider Undertale to be my second hardest game but it's an easier Touhou and it's actually fun. It's a little hard, but Idk.