I enjoyed it a lotwhen I played it, because it was pretty unique as far as Gameboy games go. I don't know if I could stand playing it today though.
If I recall correctly, you have to make it through the whole game on one life, and if you die you have to start completely over, and the game takes hours. And at the very end there's a boss fight ( a dragon I think) where the gameplay is completely unlike the rest of the game. By the time you figure out how to fight, you're probably dead. Then you have to start over...and maybe beat it the 2nd time through. It takes some dedication.
That makes it sound like it sucks, but for some reason I have fond memories of the game, so there must be something decent about it.