感謝donnie9171分享的專案 2D飛機遊戲 Thanks to donnie9171 for sharing the project 2D airplane game 滑鼠左鍵:機關槍 Spacebar: Shotgun Left mouse button: machine gun Z key: Cannon 另外，我加了散彈槍功能，以及bug修正 In addition, I added the shotgun function and bugfixes
