When Steve first appears, he protests that Dr. Wells wants him to keep going at midnight. Oscar quickly shows up and tells Steve they are flying out in 25 minutes. The scene of the plane taking off is shot in broad daylight.
When Steve and Oscar first arrive at the hospital, the car transporting them changes from a vintage 1960's-era Lincoln stretch-limo (like the vehicle that President Kennedy was shot in) with three full-size side-windows, to a standard-length current-model Lincoln Continental Town Car with two regular-size windows for the front/back doors, and one half-size window at the rear corner, behind the back door.
The Prime Minister's hat is considerably taller in the wide-angle shot of him bound to the chair than it is in the close-up shots.
The description of the villain doctor that Oscar reads off to Rudy is highly improbable --- someone who is "6-foot-two and heavy-set" would likely weight a lot more than 200 pounds.
No sign of the distant observer can be seen out the hospital window as Steve zooms in with his eye, plus the building that the merc is standing on is a different color from the buildings visible from the hospital window. Obviously a different building/location used for Steve's view out of the hospital window, as opposed to the image of the man watching on the distant rooftop, which is shown via a "dissolve wipe" of one image changing to another, not just a zoomed-in shot of the same scene.
When Billy pushes Steve backward and through the flimsy wooden barricade, Lee majors is clearly throwing himself into the fall and into the pit.