[0] .kkrieger (https://www.youtube.com/watch?v=2NBG-sKFaB0) is my favorite of this genre of constraints, but it's mainly impressive for being possible at all (and you can read up on some of the developer notes for how much effort was put into satisfying this constraint). It didn't actually advance the design of FPSes or anything, and FPS design ideas could be better learned by making and iterating on an FPS without the tiny size constraint. If students want to impose extra constraints on themselves, like developing for the Playdate and making use of its crank for game control, go for it, but it's a bit different when they're imposed from the outside for no real reason other than "hey, it's some constraints, and constraints breed creativity".