The invaders positions shouldn't all be updated every cycle, they should be updated one at a time, or in a separate thread, this is what the arcade machine does

The invaders positions shouldn't all be updated every cycle, they should be updated one at a time, or in a separate thread, this is what the arcade machine does and due to its limited processing speed this naturally leads to the aliens speeding up as fewer aliens remain. This implementation starts with the aliens going at what might be considered "full speed", and is probably much more difficult. https://www.giantbomb.com/space-invaders/3030-5099/ https://www.giantbomb.com/space-invaders/3030-5099/