(i) Display Sprites. Place main sprite in center with enemy sprites in random position around screen, but not overlapping with main sprite
(ii) Shooting. Main sprite will shoot a bullet sprite on click in direction of click; bullet speed will increase over time
(iii) Particle Effects. Upon impact with an enemy sprite, the bullet’s collision causes the collided sprite to emit particles.
(iv) Masking. Apply an oval mask around the entirety of the UI/screen’s display such that the edges of the mask cause the contents underneath to be faded out, and the center is 100% opaque. The image below shows a similar effect.