When Fridge (as Professor Shelly Oberon) jumps to the last floating bridge, he twists his right ankle and is shown limping with his right leg while he is on land. Yet, later on, when Spencer (as Ming Fleetfoot) is tending to Fridge's injury, he is wrapping Fridge's left ankle.
In "Jumanji: Welcome to the Jungle", Alex returns home to 1996, the year he was sucked into the game; 20 years before the others. In "The Next Level", Bethany and Alex are sucked into the game several hours after Fridge, Martha, Grandpa Eddie, and Milo. However when they all return, everyone is returned at the same time.
Ruby Roundhouse (Karen Gillan) is the first to fall from the airplane, followed by Bravestone and Finbar, then Shelly Oberon (Jack Black) is the last to fall. However, after Shelly Oberon stands up, Ruby Roundhouse is beyond him and walks past him on the way back to the others.
Eddie's eyeglass frames change from black rimmed in the kitchen, to rimless when he goes to bed, then back to black rimmed the following morning.
When Spencer is placing the toothpaste in the supermarket, the white side of the toothpaste box is facing front. After he is interrupted by the manager, the white side faces down.
Once the Spencer was shown studying in the New York University the sign shows New York Vniversity - the spelling of the university were wrong.
Bethany and Alex meet the other's and should both still have 3 lives.
But after the body change when they start the last mission, Bethany (professor Oberon) has only one life while Alex has 3.
Pretty much all of the instructions Oberon gives at the bridges are just random utterances of geometry terms, not accurate descriptions of the bridge configurations.
Shortly after entering the game, a plane flies overhead of the players and frightens everyone. Ruby Roundhouse (Martha) yells to the others to follow her and she chases after the plane. She would have no idea whether the pilot was a friend or an enemy to them.
When Spencer is carrying his suitcase while walking in the snow in New York, it's so heavy that he can barely carry it. When he arrives at his Mom's house, however, he has no problem carrying it at all, as it's clearly empty.
Martha's cafe states 24 hr cafe on store front, however why it has open/closed sign in window. It never says closed any particular day, only open breakfast lunch and dinner.
Grandpa Eddie and Milo were not in the basement when the game malfunctioned and no explanation is ever given how they ended up in the game, which makes their presence confusing and unbelievable.
When Milo and Eddie are discussing Spencer, as Ming, Eddie says that Ming isn't his grandson as Spencer is a boy and Ming isn't. Milo responds by squinting and asking if Spencer has changed his hair. Up until this point, Milo and Eddie have been estranged for many years and Spencer has been away at college. Milo would have no idea what Spencer's hair was like in the first place. This is borne out by the earlier scene where Eddie barely even recognised Fridge.
In the desert, Mouse (Milo) mispronounces the Australian native flightless bird Emu as e-MOO. As a zoologist he would know the correct pronunciation is e-MEW.
When Ming/Spencer opens the padlock she/he simply inserts the tools and moves them slightly up and down and it opens. This is not how this kind of lock (lever padlock) is picked. Rather, a pick inserted into the lock is used to move the levers out of the way, thus allowing a tension wrench to turn (usually about 1/4-1/2 turn) and move the bolt, releasing the shackle and opening the lock. However, no turning motion is shown at all here.
When everyone puts their hands together before entering the castle, Oberon does the "be aggressive" chant. However, he says "be aggressive, be, be aggressive". It's supposed to be "be aggressive, b-e aggressive", spelling out the word "be" - not repeating it.