I first played this game back in 1993 after a friend at school gave me his copy. My dad and I spent many hours on it but never beat it. The game shares some elements of Legend of Zelda and was, incidentally, created by the same team that created that classic title.
The story centers on Mike Jones, a typical teenager from Washington, who receives an invitation to visit his arcaeologist uncle on the island where he lives. So Mike flies there only to learn from the locals that his uncle has been abducted. So he sets off on a quest to rescue him, armed at first only with a yo-yo.
Perhaps the biggest complaint with this game is the controls, particularly in the action sequences. They tend to be a bit stiff, which can sometimes make it hard to get out of the way of an enemy. So you might find yourself cursing at the controls sometimes after you die.
Gameplay wise it features two modes. The exploration mode takes place in towns, where you can talk to people but can't make use of your weapon. Then you have the action sequences where you need to run and jump and fight your way to victory, making use of not just your yo-yo but a variety of other weapons, a few of which will only function when your life meter, measured in hearts just like Link's, is at a certain level. At the end of most dungeons is a boss monster that must be defeated, ranging in type from a fire-breathing snake to a monstrous lava beast to a giant ghost.
One of the game's highest points is its soundtrack which, though not very varied, is still excellent. Most if not all the tunes will get pleasantly stuck in your head. The sound effects are pretty much your standard NES fare for enemies getting damaged and dying. They're still pretty cool though. In fact my only real complaint with the audio is the high-pitched squeak that plays when Mike's health becomes critically low. It wouldn't be so bad if it didn't play everytime Mike jumped or used his weapon, but I suppose it makes sense if you think of it as Mike paying for the action with pain. As annoying as it can be it's not nearly so annoying as the constant beeping in Zelda or the sound they used in the second Star Tropics for the same situation.
All in all this is an excellent game that deserves a place in any NES owner's collection. A word of warning though, be sure you either have access to the game manual or to a walkthrough on the net, otherwise you won't know a certain code that's quite necessary to completing the game.