The game follows the typical lifespan of the derpy, majestic Magikarp: Fish one out of the water (hope for a shiny), train it with punching bags, match it against other Magikarp to compete for highest leap and finally retire it at level 20. (In the games, that's when it can evolve into the far more powerful Gyrados, though some would call that blasphemy.) Magikarp Jump is free on iOS and Android, though it seems the game is suffering a little of the old Pokémon Go popularity curse: I wouldn't get past the loading screen, but darn if its background music isn't catchy. It's all worth it for the Magikarp.