Atlantic City casino gambling revenue fell 9.5 percent in May to $263 million. Slot machine revenue fell 9.3 percent, to $186.9 million, while table game revenue decreased by 10.2 percent, to $76.1 million. May was a bad month for most of Atlantic City’s casinos. Aside from the newly opened Revel, only one other gambling hall, the Golden Nugget Atlantic City, showed an increase last month, and that was less than 1 percent, to $10.8 million.