I can only speak for chess, but one of the unsolved problems in computer chess is how to build a program that plays human chess of appropriate level. It is ver

I can only speak for chess, but one of the unsolved problems in computer chess is how to build a program that plays human chess of appropriate level. It is very hard to dial down a ELO 3000+ program to 1800 level of a club player and not make it computer like. What is usually done is lower the depth searched and add some random blunders but it is still obvious to a stronger player that it is a program.