Goofs

The helicopter lands close to people and their cars. After Ramsay had caught the robot, he goes back to the helicopter with her partner : you can see the people and cars far behind them. Then the chopper is taking off, it is more closer to people and cars again.

During the hotel chase scene, Ramsay runs into the stairwell and hears over the radio that Luther is on the roof. He runs up a flight or two in pursuit. Luther then steps out of the stairwell onto the roof, several seconds after the call is heard.

At the baby-hostage scene, police technicians send a "floater" (RC drone with camera), but it has only one rotor, which would never fly, because of rotational torque, spinning the craft out of control. That is why a single-rotor helicopter have a tail rotor to counteract the rotational torque. It is also possible to have TWO counter-rotating rotors on the same axle.

The arachnid-like robot spiders have six legs instead of eight. There are about 20 meanings of the word spider and only one of them has eight legs. Any object with multiple multi-directional projections gets nicknamed a spider. A scientifically oriented writer/director like Michael Crichton isn't likely to have made a mistake about leg quantities.

The rogue robot in the beginning of the film, used a Smith & Wesson Model 19 .357 Magnum revolver, which has a 6-round capacity, but the robot fires a total of 8 shots.

Strings visible on the floater camera that Ramsey sends into Johnson's house while trying to rescue the baby.

During the car chase scene, a few shots show strings attached to the little robots.

While Thompson is having the rocket removed from her arm, there are two intravenous bags set up to deliver fluid into her arm. Both IV bags have their roller clamp locked in the closed position, meaning that the IV's weren't delivering any medication.

When the domestic robot is examined, and the officer states "We've got a non-standard chip here", he's pointing at a chip marked CD4011 with the Texas Instruments logo on it. This is one of the most basic and common of all digital chips, and not at all "sophisticated", as he also puts it.

Tom Selleck's female partner Thompson wears a uniform skirt and heels in field operations, which is strictly for office or ceremonial duties. Even when she is civilian attire during the last scene, to save Bobby, she climbs on to the elevator in hi-heels, which is almost impossible to do. Women always toss their heels when they need to run or climb. Except in movies, where they don't.

When Ramsay watches Miss Rogers on the monitor as she is cornered by the sentry robot, she reacts to a Taser hit, but the arc isn't there. The optical effect is missing.

When Ramsey goes into the house to rescue the infant from the killer robot, he steps on the mini bush, the supposedly real plant is obviously a fake.

When Ramsay discovers that his son is watching a handheld TV while in bed, he reaches down and picks it up, but obviously picks up another one which has already been turned off.

When Sgt. Ramsay goes in to rescue the baby, the rogue robot is heard to cock a shotgun several times before firing its weapon. The weapon, however, is a revolver and could not possibly produce the sound we hear.

Officer Thompson has a scene wherein she describes Luther to an officer, who creates a computerized image of him using a handheld device. Why bother when they already have his image recorded on the Johnson's door monitor?

At around 0:56:03, the pot of pasta is boiling. Ramsey tells Lois the Robot to "forget it" and she erases it from memory. Eventually, it will boil dry and maybe start a fire.

When Ramsay takes Johnson to the station for questioning, he does not even put handcuffs on Johnson even though he shot at him before and behaves in a very suspicious manner.