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.
Plot hole: Mola Ram has his men knock over a vat of water in a last ditch effort to kill our heroes. First of all the vat can't be that big if it can be knocked down with a few sledgehammers. Secondly, for the amount of water that chases Indy and co. down the vat would have to be big enough to fill the room it's in, which obviously it's not. Third, Indy and co. travel through several large caverns during the mine cart chase, caverns that could easily swallow up any of the water flowing through the tunnels so there shouldn't be any water left to catch up to Indy by the time they stop.