The two I'm most happy with so far are:
Hot Foot's Castle Run - BBB0-0000-0067-50B8
Style: NSMB Castle
Concept: Long but quick castle with some secrets if you choose to look for them. Warning: the secrets are a lot more difficult to deal with than the level itself!
Difficulty: Probably a World 1 or 2 NSMB Castle.
geisthaus - DCCF-0000-0071-7F8C
Style: SMW Ghost House
Concept: Episodic ghost house challenges. Fairly linear, but disorienting by design. Attempts at a classic feel. More problem-solving than survival-platforming, though it definitely has both.
Difficulty: Cookie Mountain-ish SMW Ghost House, I think.
Sorry for no screenshots. At my GF's and away from the WiiU for the evening.