i created this effect based on this tutorial A new, community-hosted Unreal Engine Wiki - Announcements and Releases - Unreal Engine Forums
I have added a dithering effect to the post process material but its still work in progress.
When this post process is final, i want to release a small game based on the retro gaming idea.
As for now, it can look good for rendering stills, but its not that nice when in game.
Edit: Update on the Dithering, now in the right place inside the material nodes. Looks great on dark parts.