Unfortunatelly it seems your game has some bugs. One bug is in controllers menu. Doesn't show anything. Second bug is in main game when you go to the purple box it shows the effect but doesn't go to next level. Would have liked to test the main game more. (Also the "snake" seemed too fast)
But the good point for the snake mode. So nice and cool idea to have enemies in snake mode that you can kill. Nice Job for that!
One suggestion to make game better. Have somekind of crosshair for the mouse aiming. Would look nice. Also maybe your bullets could be a littlebit more visible. Otherwise the art was nice and very atmospheric music and sound effect.