I think instant engagement is a better description than instant gratification. Some books, movies, and games can pull off quick engagment but a lot have a gradual buildup as well. A gradual buildup with audio, visual, and active participation is just easier to become engaged quickly.

Some games do have rapid engagement on subsequent plays like you mentioned, although I would say COD has a pretty slow engagement for me when it starts up after an update and makes me watch those short background clips I don’t care about. Much slower than the cold open on good comedy shows or the opening scene of Jurrasic Park.