Goofs

Vargas puts the gun on the table before drinking the poisoned coffee, but the gun later reappears on his person when he shoots Billy.

When the nun at Cardenas scoops water from the fountain, the cup barely touches the water.

When Luis and the maid find the dead bird, Luis' towel is inside the collar of his gown. In the next shot he turns around and the towel is outside.

When Vargas first meets Julia, we see her from his POV and the umbrella she carries is held high enough that he has the sun in his eyes and can't see her face. When we see him from Julia's left, the umbrella is lower and there's a shadow on his face.

When Julia wakes from her first nightmare, the right sleeve of her dressing gown slips off and on her shoulder as Luis comforts her.

A pistol shot to the abdomen, even with a blank round would still cause devastating injuries. Whilst there is no bullet out projectile, the gases expelled from the gun are both very hot and moving very fast.

Around 43', Luis is thrusting but a gap in his shirt reveals that there are not genitalia involved.

At exactly 1:00, Jolie prepares for being strangled by Banderas but holding her breath, tensing her neck muscles just before he moves his hand to her neck.

At 49'08, obvious model of the La Havana port.

There is a very small piece of string stuck on Jolie's upper lip when she gives the opening lines despite the amount of care put in the actress's make up.

When Julia leans over her (presumed dead) accomplice, the camera films her from behind and her pearl earrings are revealed as "ear wires". Those were a cheap 2000's invention.

Lip fillers or silicon injections in Jolie's lips were obviously not available at the time.

At exactly 1:01'59", a flash of light on the bed sheets reveals the reflection of a camera lens or other modern equipment.

When Luis and Billy fight over possession of the gun and Billy is "shot" in the belly, why doesn't Luis notice that Billy has no visible blood or bullet hole in him?