It's arguably the best 2D metroid ever. Thats saying a lot.
And dude, just buy the bloody things. I saw Castlevania: circle of the moon for $12.00 at EB used. Megaman Zero titles usually go for $15.00 used, and you can get harmony of disonance/Aria of Sorrow on one cart now for about $25.00 used as well. Thats some serious cheap prices for so many awesome games.
And yah, my list
Megaman Zero (all of them are equally awesome)
Shining Force: Resurrection of Dark Dragon
Final Fantasy VI
Phantasy Star Collection
Megaman & Bass
Super Mario 3
Metroid Fusion
Zelda: A Link to The Past
TMNT Movie adaption (awesome retro style turtle gaming action)
Advance Wars
Astro Boy: The Omega Factor
Super Robot Taisen: Original Generation I & II