If you haven’t watched the series at all or season 3… I just gotta ask, “why not?”
The retro looking video game with its yesteryear’s 8-bit looking pixel art and blippy and bleepy sounds, seems like one you may consider passing on but from someone who almost did just that, I would like to say that you should give it a chance.
However, the game follows a lot of what happens in season 3, so be aware that playing the game or watching this video before watching the episodes in season 3 may give away some of what happen in the show away.
This first video is just an intro to the game and the epilogue and ends when Chapter 1 starts, so enjoy the gameplay video and go watch Stranger Things 3.