How can i achieve this time stop effect?


So I was playing this game to see if I can get some inspiration for my game, but then I notice something really cool. How did they keep the color correction but, also keep the players color still intact? I tried a loop that puts the player in a Viewport, its laggy so I cant really use it. I was wondering if someone could help me achieve how they did it, theirs wasn’t laggy one bit.