Here is a video showing how a NMS run should roughly go. The purpose of the NMS category is to try and beat the game "how it was meant to be played" as fast as possible, but of course if you can find a faster route that doesn't skip any large portions of any levels then by all means use it :D, it'll just be up to mod discretion as to what counts, and if it doesn't meet the qualifications it won't be rejected, just reclassified as Any%.