There are two endings depending on if you get the Rainbow Sword or not (this means that you need to complete the game with a 100% rating), If you do, you'll be able to fight the Dark Matter and see the "real" ending.

Version differences

If you play Kirby's Dream Land 2 on the Super Game Boy instead of on a regular Game Boy, when you see the title screen, you will hear an applause sound effect.

Information also contributed by Ben K

Contributed by Zovni (9308) on Jun 25, 2001. [revised by : Patrick Bregger (159431)]. -- edit trivia