What 'Elements' -make a great level?

[BitBuster]

Generally, I prefer non-linear levels, where you can choose where to start without necessarily having to follow the exact same pattern every time.

Good puzzles are those where you can see everything you need to solve it, and trying something won't necessarily cook it up instantly.

I'm tempted to agree, but then there's a level like Commit Suicide? that relies on the player not being able to see everything...and it's done in a clever way, not a "let's irritate the player with pointless guesswork" way.