Continuity mistake: When Indy tries to grab the antidote vial from the table, in the closeup just as the vial falls off the table the camera follows the vial as it lands in the empty area to the left of Lao Che's chair where Kao Kan's chair should be, but it's not, and the rug's edge with wood floor beside Lao Che's chair though it shouldn't be. Then Indy hits Kao Kan who is again seated closely to Lao Che's left, as he should be, and when Kao Kan falls backward we see the rug edge is nowhere near Lao Che's chair, also as it should be. (00:08:20)
Visible crew/equipment: After Willie spits in Indy's face it cuts to Short Round running through the mine, and just as Shorty turns his head toward the camera behind him, we can catch a glimpse of something blue which does not belong in this dark dreary environment, at the right side of the screen. There is a tall spotlight and two crew members, one is wearing a solid blue shirt and a cap, and the other a blue/white striped shirt with white pants. (01:21:25)
Plot hole: In Raiders of the Lost Ark, Indy tells Marcus he doesn't believe in magic or superstition. However, in this movie, which is set a year before Raiders, Indy not only witnesses supernatural acts, but takes advantage of them to win the day (by using the incantation to ignite the stones at the end). Therefore, by Raiders Indy would not only believe in magic and superstition but would know they exist. Listed for this movie as it was made after Raiders.
Stupidity: Lao Che's intention was to kill Indy. He had no intention of giving him the antidote. So then why would he bring a real antidote? Why not just fill it with something else instead? From his perspective, bringing a real antidote was a waste of time, and also very stupid in case Indy managed to get it, which he did. In fact, Lao Che could've brought a fake antidote and given it to Indy. He probably wouldn't have noticed the difference, and then there wouldn't have been a fight in which one of his men was killed.