Answer: houserule

AnswerCrossword Clue
HOUSERULE

Local change in how a game is played

HOUSERULE

"Dealer must draw to 16 or under," e.g.

HOUSERULE

It's not according to Hoyle

HOUSERULE
Game twist
HOUSERULE
Locale-specific regulation
HOUSERULEGame changer?
HOUSERULEGame-changing invention?