Here's what the manual
It wants you to beat all the 5 levels and rewards you with a special screen:
If it is correct that this screen is exclusive to beating all the levels, this may be considered a requirement for any% run of this game.
Since these screens are basically all this game gives you as a reward, and it seems to be doing this after every track, I don't think stopping at any particular level other than 5 can be seen as game completion.
Also it seems the game was not designed with any more gameplay in mind, if it forces you to the menu and then even crashes.
As for the code, if you mean the in-game password, such a thing can't serve as either any% or full completion goal, so it has to be really entertaining to be accepted as a side branch (similar to  SNES Biker Mice from Mars "final round" by Baxter in 05:12.62
Probably if it's that entertaining, we might be decided to allow it to stop after level 1, but this is very uncertain. Since you've already made the run, I think it's best to just submit it and see what happens.