This game holds up so well. Even if the copy abilities are somewhat primitive, there are a bunch of them and they're each distinct. The game largely handles well with some weirdness around using abilities in midair (hammer, sword) and the game lagging whenever there are a large amount of enemies on screen, which is unfortunately somewhat often. The Yogurt Yard boss is also pretty bad. But those things are ultimately minor in a game that, even being over 30 years old, is still easy to pick up and play today.