Games

There are challenge runners who've beaten the entire game with only salami for weapons. Oil puddles are just a small part of it. There was a part in act 3 where I was denied entry to a place by failing a speech check. I could have possibly brute forced my way in and murdered everyone, but instead I found a back door that was three stories up on a balcony, cast flight on my rogue, and had him stealth in to achieve the objective. That's emergent design. Solutions to problems that weren't explicitly programmed in but work because the rules are loose and can be applied intuitively. There's a part in the game where you have to cross a bridge blocked off by some high level enemies, and there are a ton of ways to get across the bridge that I know of, several of which the developers didn't intend for, and probably dozens more that I've never even seen before, because the game just lets you run loose with its systems.

That's depth.