Revealing mistake: When Ace and Melissa are in bed together having sex if you look close enough you can see that she is wearing underwear.
Continuity mistake: When Ace rescues the dog and replaces it with a toy dog, the toy dog is in an impossible position. Ace had to place it there when the door was still open, but if door was closed after that the man should have knocked over the dog.
Audio problem: At the beginning, when they steal the dolphin, you hear the peel-out sound effect as if the truck was on a paved road, but they were on grass.
Revealing mistake: At the end of the movie, when Ace is at the stadium and he attacks the mascot, his name is called and he looks up to smile and wave. He is surrounded by players from the Miami dolphins, but if you look through the crowd of players you can see the stadium seats are empty.
Continuity mistake: When Ace is in the asylum, he is trying to hide in a little cardboard box from an employee of the building, so he crams himself into a box and when the man leaves he breaks out of it. He ends up completely squishing the box underneath him. When the camera comes in for the close up shot, the farthest side of the box from the viewer is now undamaged.
Continuity mistake: When Ace is trying to work out what Einhorn and Finkle have to do with each other, his dog sits on a photo of Finkle and its hair does not cover the face, the shot moves to Ace and then back to the dog and now its hair is covering the face of the photo without even moving.
Continuity mistake: When Mr. Shikadance looks around Ace's apartment the dog door on the fridge is one piece. Later, when the penguins come out it has five strips making it easier for the penguins. The rug moves closer to the fridge too.
Continuity mistake: When Ace is sneaking into Ronald Camp's Private Aquarium, he begins to look around and open some doors. If you look at the colour of the wall it is red. When he opens the door to the giant tank, the wall outside the door (which should be red) is now white. The door also reverses - the handle goes from Ace's left to Ace's right.
Deliberate mistake: In the scene in which Ace is in the asylum, he breaks into a storage closet to view Finkle's belongings that were left behind when he escaped. At first the doorframe is such that the door closes against about an inch of wood, meaning the lock would be behind this wood, so Ace couldn't pry it open. In the closeup, the door's flush against the frame so Ace can use the sign to get between the door and the frame. In the wide shot it's back to how it was.
Revealing mistake: At the very beginning, when the guy is hanging on to Ace's car and Ace drives off, there is a shot of the dog biting the guy, but if you look closely, you'll see that the dog doesn't even open its mouth. It just sort of brushes his hand.
Continuity mistake: In the scene where Ace just gets out of the empty dolphin tank at the football field, Roger Pedacter (Football coach) is trying to stave off the media. Take a look at the sweat stain on his shirt and see how it changes sizes.
Continuity mistake: At the end of the mission impossible music, where Ace is sneaking into the billionaire's private Aquarium, there is a plant in the hallway shown from outside of the building when Ace swings opens the door. When he slams the door shut and is inside the building no plant is there.
Continuity mistake: When Ace is at the mental hospital, inside the storage room, he steps on a piece of bubble wrap. He picks it up, looks at it and throws it to the side. Throughout the scene the bubble wrap moves away from the shelves then close to them again.
Audio problem: In the scene where Ace gets attacked by Ronald Camp's shark, while he is being tossed about in the tank you can hear a crew member shout, "Great.". This may only be on the VHS version.
Continuity mistake: In the apartment crime scene, Sean Young says "we'll let you know if we find a tic", and the large grey-haired cop on her left chuckles, arms by his side. We then cut to a close-up of him with his hands on his hips, pushing his jacket to the sides, then back to the original shot with his hands by his sides again. The close-up itself is a bit weird - Sean Young should be right in front of him, but isn't visible. They must have used a later shot, because after about a minute, when everyone's moved around a lot, we see him back in exactly that position, only now the people visible fit the scenario better.
Factual error: When Snowflake is being stolen at the beginning, he makes the high-pitched noise that dolphins make even when he is out of the tank; those high peals are made underwater through carrying sound. He wouldn't sound the same out of the water as he did under it.
Continuity mistake: When Aguato takes a swing at Ace, Ace throws him down on the bug. There is no way he would have been in a position to do that, the bug was right at his feet.
Continuity mistake: In Ace's fight scene with Einhorn, he pulls her jacket down around her elbows, and she retaliates by kicking him in the groin. A split second later, her jacket is on properly again.
Continuity mistake: When Finkle/Einhorn is stealing Snowflake, he has his hands on the side of the tank. Look at which finger his Championship ring is on. Then when he puts his hand in the water, it's now on a different finger.
Revealing mistake: When Ace Ventura is checking out the tank at Ronald Camps party (looking for Snowflake), as he's holding the fish over the water, whistling and saying "Here Snowflake", you can see the tip of the sharks nose, waiting to jump out of the water.
Character mistake: In the scene at Roger Podacter's condo building, you hear the reporter mention that he allegedly leaped to his death from his own 20th story balcony. As the camera pans down, you can see the flashlights and people up on his balcony doing the investigation. This is the 2nd from the top floor. If you count the floors as the camera moves down, there are more than 20 floors to this building. The number is actually closer to 30. Even though it is difficult to get an exact count of the floors, it is still possible to tell with 100% certainty that his unit was on a floor higher than 20.
Revealing mistake: After Ace loses the guys in the car chase who kidnap Dan Marino, Ace goes hurtling through the park in his car and smashes through a picnic table. Just before his car flips you can see his windshield is smashed but no holes through it. As the car flips over the bush there is a sizeable hole in the windshield on the drivers side. Its likely the hole was for the stunt driver to look through on the flip. Ace in his car has to keep his head out the window to see anything in front of him (because of the smashed windshield). On the flip the guy has his head in the car. Later on the hole has fixed itself. We see this as Ace is driving Dan Marino to the Superbowl the windshield is still smashed but no hole and throughout the film its made very clear Ace doesn't have the money to fix it up at any point.
Revealing mistake: In the scene where Ace visits Woodstock's secret office at the music club, pay attention to the computer screen when Ace asks him to tap into the aquatic supply stores to track the sale of equipment for transporting a dolphin. Woodstock says, "All right, we got marine winch, sling, feeder fish, 20,000 gallon tank..." As he is saying this, the computer screen shows a bunch of non-related items (plates, cups, concrete, stone) with crazy numbers that don't make sense. It was as if someone was in a hurry to create a fake spreadsheet to use in the movie that they just pounded on the keyboard and a bunch of numbers came out. If you look through all of the items, it's actually funny how they are so varied (dog food, speakers, sneakers, soup, chairs) and have nothing to do with the story. Many of the items also repeat with different sets of numbers.
Revealing mistake: When Ace's car flips over you can see the left wheel is elevated over the bush. If you look closely there is a wooden plank there to help the car lift itself over the bush. The other mistake in the shot is that there is no conceivable way the bush would have flipped the car. Unless there was something very solid in front of the bush, the car would have just gone right through the bush.