The best levels in DKCR are the silhouette levels.
This is brilliance.
I think it's because the simplicity of this design forces more attention to be paid to the platforming. Or maybe it forces the designers to think outside the box and create different types of obstacles and gameplay elements than they would in a fully colored level.
I don't really want to focus only on silhouette design (though I'd love to talk about Limbo as well), because it's not this specific design that interests me here, but rather the fact that something so simple can outshine the more complicated stuff. As much as I liked Super Mario 64 back in the day, the platforming in that game is TERRIBLE compared to the platforming of more recent (and more retro) platformers like DKCR and SMG.
And beyond platformers, a game like No More Heroes was vastly improved with a sequel that does away with the overworld and 3D minigames in favor of a much simpler menu system and retro 2D minigames.
I'm just really happy that many devs have realized that bigger and badder and more complex does not always equal more fun. It's great to see some games that keep it simple and awesome.