Name the hardest games you have ever played.

[Comrade Tovya]

Honestly?   I think it depends... the hardest single gaming experience I ever had was the old Sega Genesis game "Jewels" on level 142 (see screenshot below) where literally new "Jewels" were dropping on the screen every quarter second or so and you add to move your thumbs before you could even think of where to drop the jewels.  The only reason the game ended is because after over an hour of doing this, my thumbs and my mind were worn out and couldn't take it anymore.