Camfight.Form1.Form1_KeyDown C# (CSharp) Method

        private void Form1_KeyDown(object sender, KeyEventArgs e)
        {
            if(gamestate==GameState.GAME)
            {
                GameInputControl(e);
            }
            else if(gamestate==GameState.TITLE)
            {
                gamestate = GameState.MENU;
                picShow = new Bitmap(640, 480);
            }
            else if (gamestate == GameState.MENU)
            {
                if(e.KeyData==Keys.Up)
                {
                    if (menuIndex > 0)
                    {
                        menuIndex--;
                    }
                }
                else if (e.KeyData == Keys.Down)
                {
                    if (menuIndex < menus.Length-1)
                    {
                        menuIndex++;
                    }
                }
                else if (e.KeyData == Keys.Enter)
                {
                    soundTitle.Stop();
                    play_title = true;
                    if (menuIndex == 0)
                    {
                        gamestate=GameState.INTERNET;
                        picShow = new Bitmap(640, 480);
                    }
                    else if (menuIndex == 1)
                    {
                        stage = 0;
                        single_reset();
                        gamestate = GameState.SINGLE;
                    }
                    else if (menuIndex == 2)
                    {
                        gamestate = GameState.TITLE;
                        picShow = new Bitmap(640, 480);
                        menuIndex = 0;
                    }
                }
            }
            else if (gamestate == GameState.INTERNET)
            {
                LoginInputControl(e);
            }
            else if (gamestate == GameState.END)
            {
                if (e.KeyData == Keys.Left || e.KeyData == Keys.Up) retry = true;
                else if (e.KeyData == Keys.Right || e.KeyData == Keys.Down) retry = false;
                else if (e.KeyData == Keys.Enter)
                {
                    if (retry == true)
                    {
                        reset();
                    }
                    else
                    {
                        this.Close();
                    }
                }
            }
            else if (gamestate == GameState.SINGLE)
            {
                if (e.KeyData == Keys.Escape)
                {
                    quit();
                }
                else if (e.KeyData == Keys.Enter)
                {
                    enemy.getHurt(100);
                }
            }
            if (e.KeyData == Keys.B)
            {
                show_back = !show_back;
            }
        }