I think out of all the games I've played in the past few months, the most notable is Crackdown.
That's not something you hear very often, especially since I also played Bioshock.
But Crackdown does something most other games do not do: it was fun at the very bottom. Actually pressing buttons and watching the response is a gleeful joy.
When you stop playing Crackdown and start playing another game, the first thing you notice is that the other game isn't fun. Sure, it might have great atmosphere or nifty RPG elements, but moving your character around the screen is about as much fun as eating toothpaste. I went from Crackdown to Dead Rising. While Dead Rising is a great game that I'm enjoying a lot, you move like a one-legged marmoset on tranqs. Plus, every game that's not Crackdown has a targetting system that is sheer pain.
Most games try to substitute speed for complexity. In most first person shooters, you move FAST, but your movement is not exactly deeply complex. The components never add up - you don't get the same feeling you get from simply jumping from building to building in Crackdown.
I've written on this topic before - a lot - but the fact is that most games use movement simply as a way to get from challenge A to challenge B. Even in racing games, the point of the game isn't so much racing in new and interesting ways as it is acquiring components that let you race more efficiently.
But that's giving up on the core element of the game. The very first gameplay element is how your game responds to the basic button presses. Each response should be a nice, juicy feedback loop that can be moderated into a gameplay system.
Crackdown is a really great example. Basic movement starts fluid and great, but continues to improve as you use it - and the various areas have different patterns of structures to shake things up. Aiming a gun starts easy and satisfying, but gets faster and more effective as the game progresses. Even kicking things gets more satisfying, as they fly further and further distances. I imagine that car driving gets better and better, at least with agency cars, but I didn't try, so I can't say.
Compare this to, say, Bioshock. The movement in Bioshock is pretty much limited to getting from A to B while occasionally taking cover. The gunfire in Bioshock is limited to a clumsy manual aim plus bullets flying straight forward. Every basic element of the game is flat and stale. The joy of the game comes from the parts of the game that have nothing to do with pressing buttons: graphics, story, psychic upgrades...
Comparing it to Prince of Persia is more revealing: PoP has more complex terrain, but actually has a simpler navigation: everything is "leap in the right direction, press the button when you should". It's puzzle-navigation rather than the freeform exploration of Crackdown. Which is better is a good question, but Crackdown is definitely more interactive.
If you look around, you'll see this is true in almost every game of every genre that isn't "rhythm games".
But that's just laziness. The actual pressing of buttons is the first line of game. It should have a juicy response. It is the epitome of "Simple rules, complex results."