The rules say: "Beat W1-Castle, no restrictions.

Timing starts on first input on the map (pressing right to go to 1-1) Timing stops when you grab the key in the castle.

Runs using NTR CFW are not allowed due to unfair advantages gained."

Does this mean I can just beat W1-Castle and end the run or do I have to beat all the levels from a blank or NG+ Savefile?

You have to use either a brand new file, or one that has 0 progress/levels beaten. It's the same as NSMB2.

Ok. Thanks. It sounds like an IL.