Design: Multiple Values in One Column or Many Columns?
If you created an OverTimeScore table, you'd then need to add an INT or BIT field to GameScore or Game table to check if overtime exists or not. Are you also going to store the total score? Or just each quarter score and calculate the total in your app/query? If this were me, I would add a total score field and an overtime field into my GameScore table, I don't see a reason to break it out into its own table. Populate the field if there is overtime, otherwise leave it NULL. You can then just work your queries to check is null. 101 ways...