In the final scenes with Enrique on the construction site, the foreman is seen watching Enrique. In a medium shot, he is carrying a rule or spirit level in his left hand as he looks at Enrique. In the next shot, with Enrique in the foreground, the foreman is empty handed.
The plane that taxis up to the airport building is a DC-10, but the plane seen lifting off towards Chicago is a 747.
When Rosa dies, Enrique cries and hugs her with his head on her chest. A closeup shows Rosa's hand on her stomach. The next, longer shot shows her hand is at the top of her thigh.
Whe Rosa and Enrique go through the tunnel, it is high enough for them to crawl on hands and knees, yet they crawl through on their stomaches.
When Enrique sees that Rosa has died, for a couple seconds we still see her breathing.