Games these days can render landscapes and human beings in amazing, gorgeous detail, and they're also capable of pushing complex stories and rule systems in front of their players.
But the genre's old ways haven't been abandoned entirely. A bountiful crop of independently produced games draws on retro pixilated graphics, not just for nostalgia but because it also allows entire games to be produced by a small team, often no more than a couple of devoted people.
Consider Toby Fox's Undertale. It's a riff on some of the more unusual role-playing games of the SuperNintendo era, but with more complex storytelling. The graphics look simple, but the gameplay is challenging, presenting player choices that make it possible to win without killing the monsters you encounter. The game doesn't make it easy to make the "moral" choice, and the story gets remarkably dark for those who make the fateful decision to become butchers.