Doom Captcha
vivirenremoto.github.io> Disclaimer: Don't take this too seriously, this is a little project for fun, if do you know how to code it's pretty easy to break the security of this.
I agree. This looks like the problems that are easier to solve by a computer than a human, specially because the time to react is very tight, I had to try 3 or 4 times because I ran out of time.
Anyway, if this is secretly tracking the mouse movement and analyzing it for reaction time, path and other quirks, perhaps it can detect some cases.