It might be useful to include an ID for the item's creator. I know this can be found by joining through the ItemID but keeping it in this table as well would enable faster queries concerning games inventors. It would also make it easier to stop creators rating their own games (UserID != CreatorID)
Will a user be able to revise their ratings? If so the table will need a timestamp field and possibly either a binary current/superseded field or a status field. Or previous ratings might have their own table - LikesHistory
Just a few thoughts about the Likes table: