Critical Dissonance: The film was generally thrashed by critics but fans of the series tend to receive and remember it fondly. Among many things, it embodies the general fun of the series while having entirely original footage.
IVAN OOZE. Despite having absolutely no redeeming qualities and an utter prick to his enemies, he's bound to make you laugh at some point in the movie. Being played by Paul Freeman certainly helps, and there are several reports of parents who otherwise hated the film but loved and still remember Ivan Ooze to this day.
When Disney bought the Power Rangers franchise from Saban/Fox in 2001, the sale didn't include the rights to this film and Turbo: A Power Rangers Movie, both of which Fox held onto even after Disney sold the franchise back to (the newly-revived) Saban in 2010. In December 2017, Disney announced that it would acquire Fox along with a number of other Fox assets, once again giving Disney two pieces of Power Rangers history.
LGBT Fanbase: The movie apparently had quite a gay following, and for awhile was shown frequently in gay bars after its initial release.
So Okay, It's Average: One could view it as just an extended episode of Mighty Morphin' Power Rangers or just another standard martial arts action film that just so happens to be part of the Mighty Morphin Power Rangers continuity. Either way, it's in no way a terrible movie, but there's nothing that makes it stand apart from the series or typical martial arts movies. At least it's enough to please fans and the young at heart.
Unlike in the series, Tommy keeps Saba in hyperspace instead of latched to his belt. This results in an obvious Jump Cut when he pulls Saba to finish off the Oozemen (Although not too jarring, as this is where the rest of the Rangers keep their personal weapons in the series).
The film used CGI for the Ninjazords because they didn't want to use the original props or costumes for the film. And boy do the CGI ones look bad. They're a poor match for the correct designs too.
The Ninja Mega Falconzord is the biggest offender, being based not off the full-sized toy but a smaller special edition with the wolf's head uncovered and the cover for the Ape hand being able to hold a sword (a large version of one of the Ape's Ninja-to, but the artists interpreted it as the Shogun Megazord's Fire Saber. Ouch.) Finally, they botched the head.
There's also the scene where Ivan launches the Ninja Megazord through a building and it's extremely obvious the Megazord is a model (or perhaps even the figurine) being launched through it.
Also on the topic of the CGI, at one point, the bear Zord loses its yellow coloring, then loses its blueish-black coloring immediately after. And the Ectomorphicon is standing not on the streets of Angel Grove, but the 3D animation program's grid in another scene.
There's also the scene where Ivan Ooze attacks the Command Center, the helmet on the suit that represented Alpha's head wasn't secured as it spins around 180 degrees as Alpha shakes and spins away from Ivan after he zapped him. It's still backwards while Ivan Ooze rants to Zordon. Although, you have to admit that this mistake isn't particularly bad as one generally expects from this trope. It goes some way to explain why Alpha is just yammering away in the background while Ooze is ranting; he can't do anything because Ooze jacked up his head, making it impossible for Alpha to tell what's going on.
I would have to believe that this one was on purpose. The head is shown backwards in multiple shots. Not to mention the fact that Alpha hardly moves suddenly and strongly enough in this scene for the head to go spinning around to such a degree, unsecured or not.
The animatronics used for Goldar and Mordant's heads, as well as the skeleton that attacks the Rangers on Phaedos are rather poor as well. In fact, you can see a wire holding up the tail of the skeleton in one scene.
During the skeleton fight, when Tommy is on the monster's back as it thrashes about, trying to shake him off, the camera follows the skeleton back and forth. At one point the camera actually reveals a crewman standing there watching the scene unfold.