Revealing mistake: In the junkyard, Leo and Raph grab a long pole and plough through several Foot Ninjas with it. It is painfully obvious the ninjas react to the pole before it ever hits them. Especially the guy on the ground. (00:53:20)
Continuity mistake: When the Turtles first arrive on screen behind Keno, they leap over the boy to attack the thieves. Their order from left to right when they walk up is Mikey, Leo, Donny, then Raph. The very next shot shows them in the air, and the order is now Mikey, Donny, Leo, then Raph. Donny and Leo switched places between shots. (00:03:35)
Continuity mistake: When Keno is trying to join the Foot Clan and is kick boxing with someone, the man in the background who is watching them, to see who is eligible to join, is standing cross-armed. In the next cut his arms are down by his side, and then cross-armed again. (00:43:30)
Revealing mistake: When Raphael and Keno are in the junkyard and the fight breaks out, some of the weapons bend and twist. The staves are supposed to be solid wood. (00:45:50)
Revealing mistake: There's one scene where they are surrounded by the foot. Leonardo reaches behind him for his katanas, but he doesn't unsheath them. If you look at his elbows, you can see gaps in the pads where the actor in the suit hasn't fully fastened the gloves to the rest of the outfit. (01:05:40)
Revealing mistake: In the first fight scene of the film, Keno sweep-kicks one of the bad guys. The man falls over without ever being touched. (00:03:05)
Revealing mistake: In the part where Rahzar grabs Mikey by the arms and begins swinging him around at the concert, look at Mikey's shoulders. You can see the material of the actor's body suit folding at the shoulders as it is bent further than it was designed for. (01:08:15)
Continuity mistake: When April arrives at her apartment, she places down a folder like object, and then puts some paper and her keys on them. Next she places her purse on top of the left side of the objects. Moments later, after she goes upstairs, the Turtles come in through the window next to the stuff she sat down. Now the purse is on top of the right side of the items, and the strap is in a different position. (00:08:40 - 00:09:25)
Other mistake: During the fight scene in the TGRI building, when Michelangelo has the ooze and gets jumped for it and loses it, watch the bottom of the screen. Donatello is lying down and trying to get up. But in the next shot he's up and kicks out the ooze from the foot soldier. (00:26:35)
Revealing mistake: When Donatello is messing around with the puppet, in the background the stuntmen who are fighting Leo and Mike are doing incredibly sloppy choreographies, or lack thereof, in particular those in the middle (around the doorframe) who literally run on the spot without doing anything. (00:05:45)
Continuity mistake: When the turtles are watching April interview Prof. Jordon Perry on TV, Leonardo throws the TV Guide, which lands on the table behind Michelangelo with nothing on it. After Raphael complains about Michelangelo chewing the candy bar loudly, he stands up and not only has the TV Guide changed positions, it's now lying on top of another dark object that wasn't there before. (00:16:40 - 00:17:15)
Continuity mistake: The Ooze canisters look completely different from the first movie. The canister in Splinter's flashback was the same shape but had a different label, marked "Radioactive Material" with black and yellow bars. In this movie the canisters had a plain TGRI printed in black. Also Splinter refers to the canister as being broken in half, but in his flashback it is intact.
Revealing mistake: When Michaelangelo throws the flask to knock away the canister of ooze, the ooze flies away before the flask reaches it. (00:25:50)
Revealing mistake: Once Shredder yells "Let the games begin", there is a cut on, so to say, the bleachers with the various Foot clansmember cheering and waving their weapons around enthusiastically. Their enthusiasm is too much and/or the weapons are too fake, because you can see their staves bending and jiggling like toys. (01:06:40)
Revealing mistake: Tokka tosses Leonard like a bowling ball; the Foot ninjas tumble and fall even when they are miles away from making any contact. (00:53:00)
Continuity mistake: The Turtles are looking at the computer in the TGRI lab. The Foot Clan sneaks into the room just as the computer shuts down. Michaelangelo's bandana has both ends behind his head, but they are already in front of his shoulders in the reverse shot before he turns. (00:26:00)
Revealing mistake: In the rooftop scene with Splinter and the canister of Ooze, the blurry fake backdrop is not in the least convincing. (00:21:30)
Continuity mistake: Michaelangelo does his "Wax on, wax off" little gag. Notice on the counter two buckets. The metal bucket has no rags in it...except, it does when April arrives and Mike grabs the buckets, dragging that rag back. (00:20:50)
Character mistake: When Mike fights by the concession stand at the mall, the Reuben sandwich is misspelled on the menu in "Rueben." (00:06:35)
Continuity mistake: In the sequence with Michelangelo doing tricks with the yo-yo, whenever Donatello is visible in the background he's delivering a spin kick to the same enemy. (00:05:20)
Answer: If you pay attention to the professor's explanation (starting at 0:55:55) he says "An unknown mixture of discarded chemicals was accidentally exposed to a series of radiated waves and the resulting ooze was found to have remarkable but dangerous mutanagenic properties... on our way to bury them a near collision caused us to lose one of the canisters down a sewer 15 years ago." Basically, "we had an accident and the results were dangerous and unpredictable, so we immediately went to dispose of it all." So there actually were no plans for what to do with it at all.
Garlonuss ★