“There is no need to introduce a legendary “Space Invaders” game. The most interesting feature of this project is that it uses text display for graphical output. It is achieved by implementing 8 custom characters.
The screen does not allow to control separate pixels and provides just two lines of text which is not enough for game. But it allows to implement up to 8 custom characters. The trick is to process each 5x8 pixels character as two 5x4 pixels game cells. That is to say, we’ll have 16x4 game field, which makes sense. 8 characters is just enough to implement sprites for player’s spaceship, bullets and animated aliens. Since the sprites are 5x4 and the characters are 5x8, we’ll need some characters with two sprites like “a spaceship and a bullet” sprite, “an alien and a bullet sprite” etc. All the custom characters are shown on the picture.”