This is copied from my LiveJournal, but I thought it might be interesting to some of you guys too. Feel free to agree / disagree / call me pretentious etc.
One thing Chris Crawford wrote that has stayed with me is that a sign of sophistication is smaller or more fine sensory or cognitive distinctions. For instance: kids like candy, adults like food that isn't as obviously sweet but where they can enjoy the interesting things about food tastes that kids would miss. Likewise, kids like cartoons and shows about clear archetypes, whereas adults like less obviously clear stories. This doesn't mean they're more compromising or more wishy-washy, just that they are better at seeing and knowing, so they appreciate ferreting out what isn't obvious to children. And this pattern is true of anything related to taste: the more mature your tastes, the more fine the distinctions and the more subtlety is appreciated.
This poses a dilemma to any artist: you have to create multiple levels of subtlety so that people with different levels of refinement in their tastes could all enjoy your work. There are of course works that appeal more to some than to others (and that's fine), but I think the best ones have multiple layers, where you can enjoy it as a kid and as an adult, not exclusively one or the other.
Unfortunately, artists also tend to be those with more refined tastes, simply through more exposure, so eventually they lose the ability to appeal to unrefined tastes. The better artists sometimes ignore it completely, and say things like 'well, it's not meant for beginners! only masters can appreciate my art!' (like "art-games" like The Marriage or Facade) which is an easy temptation. I think this is just as bad as the temptation to appeal only to unrefined tastes (like generic but flashy shumps or FPSs or whatever, where the focus is on clear black and whites and big explosions). Both can be done at once, through layering.
If done correctly, every element in a game should be interesting both to a 5 year old new to things like this and a 50 year old with refined tastes who has seen tens of thousands of works before yours. Every single element preferably (every character, every setting, everything that you can do), that may be impossible, but it's the goal. Classical games like Go or Chess are examples. It's fun for a kid to just move the pieces around but it also has higher levels of refinement. I know that just reflects rule-based gameplay though, in computer games this has to be done in every part of a game: the world, the characters, the graphics, the music, not just the rules.
For instance, Starcraft does this very well in terms of its rules: its rules are fun for a kid but there's enough refinement in them that people can spend years getting good at them; but that's the only part of the game that has that layering. The story is cliche, the graphics are clean but not that pretty, there's no extra-gameplay interaction worth the name, it's only the rules that are layered for the unrefined and for the refined, everything else about it is unrefined.
An alternative example is Ico: the rule-based gameplay is unrefined (basically like any other 3D platformer where you run around and hit things), but there is much more layered refinement in the story and setting and extra-gameplay interaction and all that.
My goal then would be to create something that is as layered in its gameplay as Starcraft while being as layered in the rest of it as Ico.