Looking at kittens and puppies play, I noticed that their games centered around attacking/defending, chasing/fleeing and hiding/seeking/sneaking. In the wild, those activities are crucial to survival. Juveniles like puppies and kittens are particularly fond of playing and engaging in such activities. Having juveniles who take pleasure in practicing survival-critical skills is a significant boost to fitness. For example, cats learn that seizing their opponent by the neck and raking its belly with their hind legs is very effective. They also learn the advantages conferred by sneaking and heights.
In the same way that we evolved to feel pleasure when mating and when eating calorie-dense, easy to digest food (e.g.: fatty meat), we seem to have evolved to enjoy practicing skills which will boost our fitness as adults.
What are those skills? There is attacking/defending, chasing/fleeing and hiding/seeking/sneaking which we have in common with a lot of animals, most notably mammals. What other skills have we likely evolved to enjoy practicing?
Tool/weapon-making seems to be one and games that allow you to make your own tools/weapons are often appreciated in that regard even when that feature is quite limited (e.g.: Fallout, Minecraft, Bioshock).
Exploring vast unknown territory (Minecraft, Fallout, RPGs).
Organizing/optimizing systems (SimCity, base construction and resource exploitation in RTS, character construction and development in RPGs, Clone Tycoons).
Building a base (tower defense games, Minecraft, RTS).
Coordinating with others in that way that resembles a small skirmish or a hunt (Left4Dead, FPS clans, TF2*).
What else can you think of? How can games best use this phenomenon?
*You will notice that Left4Dead and TF2 are also FPS. Part of the genius of Valve is that they’ve designed those games in such a way that even people who seldom play together will coordinate, unlike most FPS where requests to coordinate will most often result in having your sexual orientation questioned.