In the final scene in the chandelier, Barbara goes from being barefoot, to shod, back to barefoot again.
When Oliver and Barbara are eating dinner, the cutlery which Barbara is holding changes hands depending on the angle of the shot.
Before Oliver flips over the dining room table after eating the pate, the candles are clearly lit. When he flips the table, the candles are not lit.
When Oliver is hit by the pot, his top hat falls off. In the next shot when he hits the floor, the hat is back on and falls off again.
After Barbara runs over Oliver's car, we see a view from the left side of the crushed car. Then, after a shot of the dinner guests followed by a close-up of Barbara in the truck, there is a shot showing the front of the car, with steam suddenly rising from the engine. Since the car was not running, the engine would not have been hot, so there would have been no steam.
When Oliver reads the letter to Barbara that he wrote in the hospital, he says he didn't have the strength to sign it. When Oliver and Barbara are in her lawyers office, the lawyer produces the letter as supposed evidence that Oliver owes everything to Barbara. Without Oliver's signature on the letter or some proof that he wrote it, the letter would be inadmissible in court.
When Barbara cartwheels down the stairs, the stairs are clearly flat, slanting downwards, making it easier for the stunt performer to perform the cartwheels. Additionally, they are standing on a curved staircase, but the stairs on which the stunt person does the cartwheels appear to be perfectly straight.
When the 2 wires come loose letting the chandelier fall, they're shown wired directly to the fuse box without a switch - no way to control the electricity.
When Barbara is asking Oliver about the cat at the cellar sauna, the glass window is clearly evident by droplets of steam/water. The camera cuts to a close shot with both Oliver & Barbara's faces, and the glass in the window between them is clearly removed, as there is no evidence of condensation/steam. In the next shot of the sauna door, the glass is back, droplets and all.
When Oliver is lying on the gurney in hospital and the stab victim is rolled in next to him, they are so close their elbows are almost touching. In the next shot, they're significantly further away from each other and the gurneys are at different angles.
When Benny (the dog) greets Oliver as he is coming out of the sauna, we hear Benny barking, however we see him licking Oliver.
When Barbara runs over Oliver's sport car in their yard, a ramp cover with grass is visible.
At the estate auction at the beginning of the film, Oliver and Barbara bid against each other for the figurine of a woman. Oliver's auction book shows a photo with the caption, "Chinese Homunculus". The auctioneer then describes it as an "exquisite Japanese carving".
In the law library when Michael Douglas as Oliver Rose is explaining the map of the divided house, he mistakenly says "no, no, no DeVito". Danny DeVito is playing his lawyer Gavin D'Amato so presumably he got confused by the similarity of the names.