I got Kirby & The Amazing Mirror as well (for a ridiculously cheap price again). It is awesome, and despite having equal gameplay, enemies and bosses, the game is completely different. This one is a 2D platform adventurer. The only other adventure platform game I have played (that succeeded at it) was Super Mario Galaxy, so this is the only 2D.
Kirby is, the best from 2D Mario, Donkey Kong, Metroid, and a hell of a lot original stuff, in one. Truly the best 2D games.
Wow, I've been playing the games for less than a week, and I'm already a HUGE fan of them...