A clone of the arcade game "Space Invaders".
Incomplete.
See: https://github.com/axmandm/sgdk-space-invaders/blob/master/CHANGELOG.md for current progress.
Credit to https://www.ohsat.com/ for basic game logic/collision detection/entity definitions.
Credit to https://www.computerarcheology.com/Arcade/SpaceInvaders/ for further detail about game loops, sprites etc.
Credit to https://codepen.io/Griggy/full/dOKeBN for detail about shield destruction.