tl;dr: If ya played it as a kid or are getting it for kids, buy it. If you're an adult and have never played this game, it's almost certainly not going to do anything for ya, and ya should probably pass on it.
This game and any other Humongous Entertainment game should only be bought for one of two reasons:
1) You're getting it as a game for your young kids. That's how I was introduced to this game and it's stuck with me ever since. Freddi Fish, Pajama Sam, Spy Fox, Putt-Putt, they're all nostalgia mascots for my childhood and even playing this game now I still love these characters; as cheesy as they all may be now.
2) You're like me and are reliving your childhood games. Trust me, even though this game is easy as hell and you can blast through it in under an hour, it's still fun to relive a game that you enjoyed as a kid.
I spent a ton of the time I was on this game just screwin' around with the environmental stuff, which is half the fun of these old HE games. The story's stupid and would make Scooby Doo hang his head in shame of how laughable this "mystery" is, but it's still entertaining as hell to play through just so you can swim around the ocean, meet all of the Freddis' pals, and just see what you can do.