http://fenixb3.github.io/YASIC/
Yet Another Space Invaders Clone
Space Invaders is an arcade video game developed by Tomohiro Nishikado and released in 1978. It is one of the earliest shooting games and the aim is to defeat waves of aliens with a laser cannon to earn as many points as possible.
In this two-dimensional shooter game, the player controls a laser cannon by moving it horizontally across the bottom of the screen and firing at descending aliens. The aim is to defeat all aliens that move horizontally back and forth across the screen as they advance towards the bottom of the screen.