A simple and clever twist on the twin-stick shooter: the one-click shooter!
Great artwork, cool background and fitting sound effects. All it was missing was a little juice, like screen shake when you fire. You might also consider adding a bounding box to prevent the player from reaching the far edges of the screen, to make moving themselves away from walls a little easier, and prevent enemies from unfairly spawning right on top of the player.
Good fun otherwise, I rather enjoyed. Well done, and good luck!