A very new FPGA developer is very stuck. I think I have timing issues

Works perfectly :). here is the modified code if snyone else has this issue:

module binaryShift(
	// this is the 50MHZ  onboard clock 
	input CLOCK_27,
	//push buttons
	input  KEY,
	//dpdt switches
	input  SW,
	//7-SEG Displays
	output  HEX0, HEX1, HEX2, HEX3, HEX4, HEX5, HEX6, HEX7,
	//LEDs
	output    LEDG,  //  LED Green
	output    LEDR,  //  LED Red
	//GPIO CONNECTIONS
	inout    GPIO_0, GPIO_1
);
// Blank the unused HEX displays
assign HEX7 = 7'h7f;
assign HEX6 = 7'h7f;
assign HEX5 = 7'h7f;
assign HEX4 = 7'h7f;
assign HEX3 = 7'h7f;
assign HEX2 = 7'h7f;
assign HEX1 = 7'h7f;
assign HEX0 = 7'h7f;
//assign LEDR = 18'h12;
reg paddle;
reg pressed;
initial
	begin
	paddle <= 18'b111100000000000000;
	pressed <= 1'b0;
	end
always @( negedge CLOCK_27)
	begin
	if (KEY)
	begin 
		pressed <= 1'b0;
	end
	if(!KEY && !pressed)
	begin
		pressed <= 1'b1;
		case(paddle)
					18'b000000000000001111 : paddle <= 18'b111100000000000000;
					18'b000000000000011110 : paddle <= 18'b000000000000001111;
					18'b000000000000111100 : paddle <= 18'b000000000000011110;
					18'b000000000001111000 : paddle <= 18'b000000000000111100;
					18'b000000000011110000 : paddle <= 18'b000000000001111000;
					18'b000000000111100000 : paddle <= 18'b000000000011110000;
					18'b000000001111000000 : paddle <= 18'b000000000111100000;
					18'b000000011110000000 : paddle <= 18'b000000001111000000;
					18'b000000111100000000 : paddle <= 18'b000000011110000000;
					18'b000001111000000000 : paddle <= 18'b000000111100000000;
					18'b000011110000000000 : paddle <= 18'b000001111000000000;
					18'b000111100000000000 : paddle <= 18'b000011110000000000;
					18'b001111000000000000 : paddle <= 18'b000111100000000000;
					18'b011110000000000000 : paddle <= 18'b001111000000000000;
					18'b111100000000000000 : paddle <= 18'b011110000000000000;
					default: paddle <= 18'b111100000000000000;
				endcase
	end
	else if (!KEY) begin
		paddle <= ~paddle;
	end
end
assign LEDR = paddle;
endmodule

now, So I added the "pressed" register so that it didn't keep cycling the case statements while the button was pressed, is there a better way to do this code?

Like I said , I am still very much learning and any critique of my code will be very much appreciated.