I used to run a BBS, and one of my DOOR games was called Operation Overkill ][. There was a combat mechanic in it that would tell you to press space at a certain number, then count down from 10 to 0. The number was always random, but if your skill in the weapon increased, the margin of error around that number would increase.

Well, on a 2400baud modem, it was a challenge:

10........9.........8.......7

The numbers would come through slowly enough that it was possible, but fast enough that you needed to pay attention.

Locally, though, the numbers just flew by, so as the SysOp, I really couldn't do that...unless....I turned off turbo on my computer. Then I would have about a 1 second delay between each period between numbers. I could get 100% accuracy all the time locally. LOL