All the rules of chess apply, except that White makes 2 successive moves per turn.
Sometimes White's moves can be executed with humor. For example, both hands can be used to move 2 pawns simultaneously, or a Black piece one square away from the White King can simply be removed from the board. Queening a White Pawn generally allows White to declare a checkmate the next move. Also, with only the 2 Kings on the board, White can easily force a Monster Chess checkmate.