Specifically this thread will be making comparisons between the 1990 movie vs. the 2014 movie and Secret of the Ooze vs. Out of the Shadows. It's ok to mention other franchises and movies but they're not part of the main discussion so keep it brief and only when absolutely necessary.
The goal here is to compare the individual movies first. That's why it's set up to be original vs. original and sequel vs. sequel.
Then to determine which live action Turtles franchise is the best over all... totally ignoring the third movie existed because the new version doesn't have a third film to compare it with... yet...
I have not seen Out of the Shadows yet so I'll talk about the sequels at a later date. For now though 1990 is clearly the better movie.
First of all, both movies made changes to the characters origins. However the 1990's movie made changes to their origins that actually improved the story while the 2014 version made changes that made their originals even more confusing than the original version.
Original: The mutagen causes people and animals to mutate into the last thing they had contact with. The turtles became humanoid because they had contact with Hamato Yoshi. Hamato Yoshi turned into a rat because the last thing he had contact with were the rats that lived in the sewers. And if you haven't noticed the huge plot hole in that already let me explain. If the turtles became human because they were in contact with Hamato Yoshi then Spinter should also be a turtle because the last thing he touched was the turtles not a bunch of rats. If Yoshi turned into a rat because he was in contact with them then the rats should of mutated into humanoids not four random turtles. And if there's three species involved here that all had contact with mutagen at the same time then shouldn't they all be human/rat/turtle hybrids? The way the mutagen works makes no sense.
1990 changes: Rather than Splinter being the mutated form of Hamato Yoshi they are instead separate characters. Splinter was the pet of Hamato Yoshi. They also changed how the mutagen works so all animals just become humanoid. This eliminates all the confusion of how exactly the Ooze actually works. This is a change from the source material that actually improves the story.
2014 changes: As far as I can tell Hamato Yoshi never even existed. In both the source material and original movie it's Hamato Yoshi who either directly or indirectly teaches the turtles to be ninjas. Directly when he is Splinter, indirectly when Splinter is his pet. But in this movie Splinter learns martial arts from a book he found in the sewer... WTF? Technically he's not even qualified to teach them as he's just learning himself. In every other version he was already a master before he met the turtles... as unbelievable as it is for a pet rat to learn martial arts it's actually far more acceptable than someone throwing away a book and an illiterate rat some how being able to learn from it. Not only that but this new origin makes it so this Splinter originated from New York rather than Japan like the other versions... so why does he have a Japanese accent and look like a Japanese stereotype if he's never even been outside of New York? This Splinter is just racist. Another change they made here... the original movie kept his rivalry with the Shredder because they knew each other back in Japan. This version... they've never met before. Every other version of this story there's a reason why Splinter and Shredder hate each other but in this version their history is completely non existent. These changes don't make the story better, it makes it worse.
The only thing those changes actually fix is that no version of this franchise has actually explained how Splinter came to New York from Japan. The origin story always skips over that part. Just he use to live in Japan and now some how he's living in the sewers of New York. I don't think it's ever even been explained why he left Japan at all. This movie eliminates that problem by making him a New Yorker to begin with but creates a whole new set of problem by keeping him Japanese despite having no Japanese origins. A change I would of liked to have seen that would of made the origin story better rather than ruining the movie... would be if they actually for the first time explained why and how Splinter left Japan and ended up in New York. Seriously I don't know of any version of this franchise that has actually told this story and I really want it to be told. Instead we got this crap which is the worst retelling of the turtles origin ever made.
Moving onto the rest of the plot... 1990 had some holes... it was not perfect... However you have to seriously look for those flaws. With the 2014 movie the plot holes are so big you can't miss them. Dude leaves behind a turtle because he thinks he's dead. He needs their blood, they don't actually need to be alive for that. They also never bother to take Splinter even though he also has mutagen in his blood because... I don't know the movie never even tried to explain that one. And the whole goal of the bad guy's evil plan was to make him rich even though he's already rich. And Shredder doesn't actually seem to have a reason for helping this guy... he's just in the movie because he's suppose to be in the movie. Technically speaking the rich white guy was originally going to be the Shredder but people complained so much revisions were made at the last minute which is why the Shredder seemed like such a undeveloped throw away character rather than the main bad guy.
Character designs... in regards to the turtles... I'm not going to make this a practical effects vs. CGI debate. I will mention that the originals were actors in costumes because this was back before CGI even existed. But that's not what makes them better. What makes them better is that the new Turtles are on steroids. These are the largest turtles we've ever seen before... which should actually make them even harder to be stealthy ninjas when they're that freaking big.
In regards to the Shredder... even though he was a pointless character he still has an awesome design. A lot of people have complained about how the Shredder looked in the 2014 movie but that's actually one of the better versions of him. The 1990 version was great at the time but looking back on it now, it's not the best look for him. Not the worst but the 2014 armor design actually did better.
Over all, the 1990 movie is clearly the better movie. There's very little in the 2014 version I actually liked and nothing that is significant enough to save it from being a terrible movie.
All this being said... judging from the trailers I have a feeling I might have the total opposite reaction to the sequels. I won't know for sure till I actually see Out of the Shadows but considering the cast of villains we got is something I've been waiting to see since 1990 which we never got, it might be a bit hard to make the sequel as bad as the original. For those that don't know who have never seen the original trilogy... Instead of Bebop and Rocksteady we got Tokka and Rahzar... They were in one episode of the cartoon and I don't even remember them but Bebop and Rocksteady were main villains who appeared in every episode of the original cartoon and those are the villains I wanted to be in Secret of the Ooze... they never appeared in a live action film until now. Another character who never showed up in live action before is Krang. Instead the original movies had a large bald man who vaguely resembled Krang's mandroid body except he was never revealed to be a mandroid and communicated only in a series of grunts. There's also the scientist who helps the Shredder create his own mutants... Originally it was Baxter Stockman who was intended to be a villain and he's in the new movie. However in the original trilogy this character was changed so that he wasn't actually evil but instead was being forced to help the villains and after being rescued ended up helping the turtles instead. Not only did they change him from being a villain to a hero but they didn't even call him Baxter Stockman... which is weird because even with the changes I always thought he was Baxter Stockman. So as far as I can tell from the trailers at least, Out of the Shadows is actually closer to the source material than Secret of the Ooze which is odd considering the first movies in the franchises are just the opposite. Anyway, more to come after I have a chance to actually see the movie.
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