Secret Level has these relationships to other tropes:

parents kids shares a parent with:
Story Branching
Unlockable Content
Brutal Bonus Level
parent child
Story BranchingMultiple Endings
''Multiple Game Openings
''Golden Path
''Mutually Exclusive Party Members
''Story Branch Favoritism
Unlockable ContentDouble Unlock
''Secret Character
''And Your Reward Is Clothes
''Post End Game Content
You'll need to Get Known if you want to add or modify these relationships.