using multiple columns as a primary key doesn't appear to be addressed in dbutils. i scrolled through the class a little. sqlite requires a special syntax: PRIMARY KEY(column_1,column_2,...). i didn't see it.
dbutils appears to assume a single column. you might have to do it via a direct sql1.exec ("create table ...."). you could try passing array as string ("game_id", "user_ID") as your 4th parameter, but i'm not hopeful. you might try fooling around with putting "game_id,user_ID" in parentheses since that's what sqlite wants to see, but i'm not holding my breath on that one either.
you could have a primary and an index, but it looks like dbutils doesn't create indexes. i've always used sql exec calls, so i can only relate what i saw looking at the dbutils class.