Music - I reccomend something like Distort.Mod or Space_debris.mod, if you're using a happyish tileset. If you want to use a dark, dangerous tileset, use happy music like the Final Fantasy music or something. In other words, make sure the music fits in no way whatsoever.

Tileset - definitely one of Agama's or Disguise's. Any self-respecting n00b would go for a good-looking/popular tileset, thinking that the fact that it uses such a wonderful tileset makes up for the fact that the level sucks. Personally, I'd suggest Swamps of the Jaguar, since it's pretty good, or Sirius, since some people seem to hate that tileset.

Level - either copy the layout of VCTJ 1 (I took teh level and made it better ) or make a huge level where you have to solve a puzzle for every single red gem. Hey, it wouldn't be a 30-second level any more, would it?