Fun = Satisfaction + Flow State.
It’s that simple. Think of it like that and you’ll have a useful, actionable and practical definition for the classic definition of game-generated fun.
People use the word ‘fun’ for lots of things (notably any positive experience with no clear long-term value, such as a ‘fun movie’), but nearly all uses of games we consider fun follow this formula. While people might call the Stanley Parable fun, it’s not the kind of fun we associate with classic gaming. This is because it lacks a flow state. It’s not activity-based fun. However, it does come with buckets of satisfaction (taking actions that make the narrator react in amusing ways).
Let’s clear up some more definitions while we’re at it:
A “good” game is anything that creates a positive experience for its intended audience. This doesn’t have to be in line with our first definition of fun. Many players will call these games “fun” for want of a better word, but that fuzziness is what creates arguments about what “fun” is in the first place.
A “well-designed” game is anything that accomplishes its creators’ design goals.
A “very well-designed” game is a well designed game that accomplishes its goals more elegantly. You’ve got to hit the design goal to be well-designed. After that you get bonus points not for adding more features but for stripping unnecessary ones away.