Both eliminate nuts and seeds in the introductory stages, but GAPS introduces egg yolks early on (if tolerated) and nut / seed butter in later Intro stages (thehealthyhomeeconomist.com)
There are nine fairly large levels (and a quick intro stage) in Angry Video Game Nerd Adventures, and the game can be completed in a few hours if you get through levels smoothly. (nintendoenthusiast.com)
This list won't solely include intro stages, it will include some intro videos as well, something you just watch before you even really need to pick up the controller. (entertainmentbuddha.com)