When Sylvia opens the chest in the lounge and finds the skull, it is facing forward. In the longer shots, thereafter, it is facing upward toward her.
At 13:25 when Leo tests the secret door closing/flooding device, the door closes from inside the room to outside. However, at the end of the movie when Jack pries open the door to see the bodies (presumably), there is no way that he could have pushed the door open with the water pressure behind it.
Although the credits name George Zucco's character as 'Leo Grainer', he is referred to throughout the film as 'Leo Grainger'.