Your favorite "traits" of game design

It's difficult to phrase it the right way in the title, but I'll try to explain what I mean.

I've noticed that the games I'm finding the most fun now are games that are easy to pick up and play, but have depth to their play mechanics and movement. And can be put down quickly, due to having either frequent save points or levels that aren't too long.

For example, Steel Diver has been surprisingly fun (though lacking in content for a $40 handheld purchase), and the depth comes from the challenge in controlling your sub and reacting to things in time, as the play mechanics are rather specific. Yet, it's simple to learn the basics of playing the game. Although levels have 10- and 15-minute time limits, it's easy to hop into. I also like the Super Mario Galaxy series, as they too are simple and save after every mission, all of which are short.

I find myself now more intimidated by games with lots of complexity, long levels (I used to love Wario World, but later found myself unwilling to play it because levels could take 20 to 30 minutes each!), and games which take a long time to get interesting due to long intros and story stuff (such as Kingdom Hearts 2). I could still get into a 2D Metroid, due to their simple goal (find next boss or entrance to next area), and frequent save points, but got bored easily with Metroid Prime 3.

Another thing I'm noticing I like is games that give you a fair amount of freedom with upgrades and doing things in the order you like. My brother and I have been doing a Mega Man X marathon of sorts, and it's been fun getting the upgrades, exploring the levels for the hidden stuff, and so on. Yet the gameplay still remains simple at its core, and fast-moving.

So, what types of games do you find yourselves playing? Are there specific traits they tend to have in common, such as pacing, or certain design elements?

I too have always enjoyed games that allow a fairly high level of customization and yet somehow manage not to have impossibly steep learning curves. For example, there's an old Sega Genesis game called Cyborg Justice that I used to love. It was a very straightforward side scrolling beat'em up, but it allowed you to customize your 'borg with different equipment. This feature alone made what was otherwise a forgettable game pretty awesome for me.

But despite enjoying customization I also tend to prefer games that are less sandboxy and more focused in their objectives. I like to be guided a little bit and I dislike being constantly offered multiple choices at every turn. That isn't to say that I never like having to choose a path, it's just that I prefer less choices to more.

But despite enjoying customization I also tend to prefer games that are less sandboxy and more focused in their objectives.

Same! If I can do whatever I want and that's the goal, I get bored. If I have a goal but still have freedom to do what I like along the way, then I have a lot more fun. I think "freedom within a goal" works best for me.