>How do you do screen flickering?
Anon, there's a whole website dedicated to that: https:// nesdev.com
But your title is optimistic as fuck. If you focus on just implementing the restrictions and methods, you get a tech demo - not an authentic game. We have newer hardware that makes it easier for you to focus on the game while actually keeping the aesthetic you want.
Here's a foolproof way to make your pixelshit stand out from everything that's being released and have it be authentic - actually design the game and focus on artwork and sound instead of autistically obsessing over self-imposed programming challenges. If your models look like good NES-era art and not generic hipster low-res vomit that looks like somebody scaled up Atari textures, it will be very noticable. But feel free to ignore everything I just said and go to the website anyway, that still answers your question.