Bonus Feature Failure has these relationships to other tropes:

parents kids shares a parent with:
Power Up Letdown
parent child
Powerup LetdownUseless Useful Spell
Power Up LetdownAwesome But Impractical
''Cool But Inefficient
''Promotional Powerless Piece Of Garbage
''Scrappy Weapon
You'll need to Get Known if you want to add or modify these relationships.