15 Gameplay Glitches That Actually Became Features In Video Games

Difficulty Curves in Space Invaders

Originally, the aliens in Space Invaders were supposed to all move at the same speed throughout each level. But developer Tomohiro Nishikado realized that hardware at the time couldn’t run the game as he intended. He discovered that once you killed some of the aliens, the game would speed up. Essentially, have so many aliens on the screen at the start of the game forces a major dip in the framerate, and the more you kill, the less the computer has to deal with, and thus making the framerate climb to where it’s supposed to be. This, of course, made later stages of each level more difficult, making the game more difficult as time went by.