I use only Unity so i supose i can create a Linux and Mac version after the Jam for each of my games. It's fun because I tought the first time I created a game that unity would automatically configure my games for all platforms. So some people with mac and linux tried to download my game and i never had feedBacks :) . So yes i can create a Mac version but i will maybe never test it. My 3 first games perfectly works on an old laptop PC so i suppose i will have a chance that it works on the linux and mac platforms.
For The games "Morning" and "Neon matrix" i used primitive shapes like Sphere and Cubes and i changed the Color and the scales randomly(It's very instructive to do first games like that). It's almost only coding.