you can also read about it on wikipedia.

also, the japanese name of it is Doukutsu Monogatari - in english its called Cave Story

easily one of the best games i've ever played. check it out at www.miraigamer.net/cavestory

there's 2 downloads. 1 is the game, the other is the english patch.. also, check out the player controllers application before playing (the controls are super simple, nothing to get an asthma attack over). 

anyway you can also read about it in the site.  the game has quickly gotten a huuge cult following around the world.  i was surprised gamespot had nothing on it. anyway enjoy