Do I need to pass Spamton NEO on a snowgrave, or is it enough to get by with a secret boss (It's the same boss)? Also in the rules it is indicated that the passage should be in one save file.

all bosses requires main route neo and queen/gigaqueen

Okey, thanks

As of right now, it’s impossible to fight Snowgrave Spamton NEO, Queen and Giga Queen on one savefile.

For Chapter 2 All Bosses, you must beat Spamton NEO (basement), Queen and Giga Queen. All must be done on 1 savefile