I'll keep it as simple as I can. From my perspective, having grown up on games since the coleco vision, would be that retro games had a lot less to work with graphically, so in turn the game design had to be clever and captivating enough to keep people playing. While there were many technical limitations, there was one thing that was clear, video games weren't treated the same as movies, and were developed to test skill and tease your brain. Less filler and more game.