[Rhapso]

well, extract a good metric for "fun" (like engagement) and make that the optimization criteria. It would be equally as easy.

[adastra22]

There is no good metric for fun.

[mattigames]

Call of duty occacionally asks you after a match if you had fun (5 options from "boring" to extremely fun), I bet thats a good metric for fun.

[teamonkey]

Heart rate, pupil dilation, breathing rate…