Continuity mistake: As Griffin is telling J that K has to go to the Apollo launch, the shot from his perspective shows J holding his nose from where K punched him, his hand being over his nose. The shot cuts to show Griffin's face and suddenly J is wiping the underside of his nose. (01:16:35)
Continuity mistake: When Boris is about to french kiss the woman, she opens her mouth wide and approaches him; then from the opposite angle the mouth is closed and she is walking towards him again. (00:02:30)
Continuity mistake: When J and K fall off the roof holding onto a door, they land opposite to each other. A frame later, from a different angle, they're laying next to each other. (00:17:55)
Character mistake: Griffin states about the New York Mets saying "They were in last place every single season until they won it all". That is not true. They came last ever since they started in 1962 to 1967. In 1968, the year earlier, The New York Mets came second to last where as The Houston Astros came last. (01:07:30)
Continuity mistake: When J steals the blue car keys, a nerdy looking guy with an orange and white striped shirt and glasses is walking towards the hotel. After J drives zooming through New York, the same guy is seen crossing the street walking the opposite way. (00:39:15)
Continuity mistake: When J exits the Flatiron building in 1960 a woman walks right behind him, then the shot cuts to his POV of a group of hippies, then back to the previous shot of J and the woman obviously continues her walk. She should've been several meters ahead already. (00:38:30)
Continuity mistake: After K is falling with J from the rooftop, big chunks of concrete start to fall, yet disappear in some shots. When they land, the ground is clean, yet in one of the close-ups of K a chunk magically reappears next to his head. (00:17:50)
Continuity mistake: In the Headquarters in the altered time line, when J is crying out that he and K spent 14 years of stakeouts, cowboy music, etc. A woman in the back swaps from standing by a screen to walking 20 feet to the right, between shots. (00:28:40)
Continuity mistake: When K tells J he's suspended after asking about Boris, they get into a brief confrontation about it. As K is storming away to take the car, leaving J back at Wu's without a ride, J's suit is still dirty, wet, and nasty from his fight with the alien fish. Moments later, J is seen going to MiB headquarters and now his suit is clean and in perfect order. (00:19:45)
Factual error: Just after Griffin finishes telling J and K that the Boglodites destroyed his planet, Boris appears on his motorcycle and snatches Griffin. J, K nor Griffin didn't see this coming whatsoever, until Boris appears. The main problem with this is that motorcycles have very loud engines, so whilst J, K and Griffin may not have seen Boris as they weren't looking at him, at least one of them should have definitely heard the sound of the loud engine coming from Boris' motorcycle. Plus, the sound from the game that Griffin was foreseeing wasn't even that loud so the cheering from the audience certainly wouldn't have intervened with anything. (01:09:00)
Continuity mistake: As J is being put in the "big ass neuralyzer", they first have him in front of it strapped in a metal bracket. As they begin turning him upside down, the white suit guy on the right reaches over and begins opening the hatch on the neuralyzer. You see him turn the handle and hear the creak and see it slowly crack open for a moment before the shot cuts. Then two shots later as the white suit on the left is about to put the bite guard in J's mouth, the hatch is suddenly closed and the guy on the right is reaching over to open it again. (00:46:10)
Revealing mistake: During the time jump, there are several points in which it is apparent that J has been animated. (00:36:05)
Factual error: Apollo CSM is venting something through RCS thrusters in the scene on the launchpad. It is not correct, because RCS works on aerozine (UDMH, hydrozine) that isn't cryogenic fuel. Also, video/photo from the actual launch doesn't show this venting: http://spaceflight.nasa.gov/gallery/images/apollo/apollo11/hires/s69_39525.jpg http://spaceflight.nasa.gov/gallery/images/apollo/apollo11/hires/s69_39961.jpg http://spaceflight.nasa.gov/gallery/images/apollo/apollo11/hires/s69_39962.jpg http://spaceflight.nasa.gov/gallery/images/apollo/apollo11/hires/s69-39529.jpg http://youtu.be/zGNryrsT7OI. (01:21:45 - 01:24:35)
Continuity mistake: When Jeff is talking to J on the Flatiron, he is looking at J except for a brief shot where strangely he is suddenly facing left without having turned his head. Then a frame later, from another shot, he is back facing J. (00:33:50)
Factual error: When J is driving to Coney Island and is stopped by the two police officers,the view of Coney Island in the background is wrong. You see the Wonder Wheel ferris wheel and to the right you see the Cyclone roller coaster. The only way you could see the Cyclone to the right of the ferris wheel would be if you were on the boardwalk, on the beach, or in the Atlantic Ocean. (The tall cylindrical ride between the coaster and wheel is verification that the roller coaster shown is the Cyclone.) In addition, in 1969 there were two other roller coasters - one of of which would've been seen in that view - the Tornado which would be to the right of the ferris wheel which means the proper view should be two roller coasters with the ferris wheel between them. (00:41:45)
Continuity mistake: Before leaving in the jet packs to go to Cape Canaveral, O steps off K's jet pack twice between shots. (01:19:25)
Continuity mistake: On the Apollo docking bay, just as J says "You're gonna lose", Boris has J pinned up against the scaffolding. Then as Boris says "Let's agree to disagree", J is suddenly not pinned against the scaffolding, leaning forward. J also goes from looking ahead to looking down. (01:28:35)
Continuity mistake: When Griffin shows J and K the vision of the baseball game, J walks back and then walks back over to Griffin. Griffin then places his arm around J and his hand ends up around the top of his arm. In the next shot, Griffin's hand is suddenly on J's shoulder. (01:07:05)
Continuity mistake: When J and K are talking to Agent W backstage, as Agent W says "You're out of your mind...", he is looking straight forward at K, head remaining still. Next shot, he is looking at K with his head is suddenly shifted to the left. (00:56:05)
Audio problem: When Jeffrey Price asks J what is the plan, J replies "You're going to send me back to July 15, 1969." Two shots are shown as he says this line. The first shot shows a reverse angle of J starting to speak the line, however, his jaw is never shown moving. This line would require his jaw to move. (00:32:20)
Answer: Earlier in the movie, the way K was talking about Boris was different than what J had come to expect of his partner. So J wanted to know what happened between Boris and K at Cape Canaveral that changed him. So more of what did Boris do to K rather than just the report of what K did.