Continuity mistake: When Rains spits on Haskell shortly after meeting him, you can see the spit trailing downwards. In the next shot, however, it inexplicably lands on Haskell's cheek, who's a good foot taller than Rains.
Continuity mistake: After Ryjkin is doused in acid, he begins to bleed on his shirt, partially obscuring his name that's stitched into the shirt. A few shots later, as he starts to pull his face off, the name is completely free of blood.
Continuity mistake: When Wynn enters the elevator, location arrow points to direction 1 o'clock between down and up. Elevator starts to lower, but now initial position of arrow has changed nearer to up position, to 2 o'clock.
Continuity mistake: When Meyerhold throws the boots into the ice room, you can see it spinning, and there is absolutely no shoelace trailing off it, yet he somehow manages to pull a shoelace from the now broken shoe.