In an interview, the game's director and designer Hiroji Kiyotake was asked about the characters and sprites looking different from other Mario games. He responded: "With Super Mario Land 2, one of our ideas was to not be bound by the conventions of the previous games. However, when we showed our first draft to everyone, they were like, “I don’t know… is this Mario?” We realized we were on the wrong path, so we toned down that idea and made something a little closer to the existing Mario world."
Contributed by ProtoSnake