Yes, it's very important to get the Djinn and not to miss one, your help book from Amazon will give you a good head start on where you might encounter these creatures.
Wow, what an awesome game, you make me want to pick it up again. I think I spent about 30 hours on the first one but at least 10 of those were looking for a sword that never appeared. It didn't matter as game 2 had a better sword in the end anyway

Literally one of the best games of all time. Good ol' Ninty