A relatively unknown movie series to many, 3 Ninjas eventually lost their charm too. The first one was a great, funny kids movie that really made them seem like ninjas, but with the kiddie feel so it's not all too serious. All three kids were great.
Then came 3 Ninjas Kick Back where they go to Japan and meet a girl that also helps them save their grandfather, who won this dagger long ago that his old rival wants to steal to open some legendary Cave of Gold, etc. I have to say this: the nurse that is taking care of the grandfather in the hospital was the cook from the movie Clue! Anyway, this movie was actually an alright followup, even though 2 of the 3 ninjas were different actors. It was also annoying how the youngest Ninja did pretty much no karate at all. He couldn't even climb a rope, the other two had to push him up before they started climbing.
After that came 3 Ninjas Knuckle Up. This one was originally filmed before 3 Ninjas Kick Back, so it had the original three kids, which is always better. The movie itself was a bit low on plot and not as interesting. The 3 ninjas are at their grandfather's cabin like they are every summer, and this time they meet this indian girl Jo, who says that this bad man that runs the dump is illegally dumping chemicals on the indian land, which is killing off the indians. The bad man captured Jo's father, because he had some proof on a disk that showed that the evil guy was guilty. So the 3 Ninja's help out! The fighting was entertaining, and the plot gave a nice gesture, but it seemed like it was still just a small-town plot; it was as if the movie was the kind you buy directly on video. When you saw it, you wished more was at stake, or that something would happen at the end that made them seem like real heroes. But then the moral of the movie was that a ninja must listen to the flower when it blooms: (When it blooms, it says nothing! It doesn't want to show off how pretty it is, it just wants to be pretty.)
This is where things really got off track. They made 3 Ninjas: High Noon at Mega Mountain. All 3 kids were different. They don't even look like the original. Grandpa only appears briefly. The bad guys weren't just dumb, they were completely evil and rude and hurting innocent people for money. And Hulk Hogan is in the movie. Bad plot, bad characters, unlike the original. It was just sad, really. I own the previous three, but not this one, and for good reason.
So indeed, sequels are often a lot worse than the original. Or something like that. Go see the original 3 Ninjas, it's like being eight-years-old all over again!
