Genre kits for Playground games: platformers, racing, shoot 'em ups, fighting and more

What the games of a genre share, on top of the Playground: a platformer's tiles, ladders and slopes, a racing game's road and cars, a shoot 'em up's shots and flight paths, a fighting game's hit boxes and frame data (and its fighters as 3D skeletons), mazes, grid puzzles and Sokoban's solver, cards, an adventure's world and sentences, a real-time strategy's orders, a team sport's formation, a rhythm game's clock and charts, and the levels of Doom, Descent and Comanche. Each is a library of its own, elm_playground_gamekits.<name>.