Factual error: When the Security Guard in the pump room gets bitten on the nose, he starts shooting with his revolver (a SIX shooter). Count the bangs. He manages to fire SEVEN times. (00:39:45)
Revealing mistake: The Gremlin who throws the beaker full of acid has his arm operated by a stick, which is visible as he chucks the beaker. (01:08:05)
Continuity mistake: As the crazy Mogwi changes from a ball to an actual creature, a can suddenly changes position on the shelf above, though nothing touches it.
Revealing mistake: When Henry Futterman is attacked by the winged Gremlin, most pedestrians just pass by, only glancing occasionally at Dick Miller's frantic performance, since the Gremlin was only inserted. Only when Futterman smashes the pest into the wet cement, the Gremlin is the 'real' thing. (01:02:35)
Deliberate mistake: The elevator operated by gremlins starts ascending at around 5 stories per second, based on the floor readings. Yet when the elevator suddenly stops dead, Kate does not fly into the air caused by the huge speed change. (00:50:05)