In the storage room, Steve is supposedly using the juncture wire to ring the guard's phone and keep him distracted. But in one shot Steve is seen helping Logar out of the block while the phone rings, meaning there's no one to trigger the ringing.
In the closeup when Steve hooks the mesh ladder to a drawer handle, the handle seems to be barely within Steve's reach as he lies on the desktop. However, in a later long shot, the handle is shown to be much farther than Steve could have reached in that position.
Despite the fact that Joe says earlier that the ion propellant is radioactive, and there is a big "Danger - Do Not Approach" sign next to the propellant storage box, no one seems concerned about radioactivity. The guard comes right up to the box, removes the lid, and peers inside.
It is stated that a chemical process is used to shrink Joe/Logar. However, a chemical process would not account for the tons of extra mass that Joe loses, and later regains within a minute upon his death.
Steve tells Joe that they should both split up and head for the camp. But Joe has no idea where the camp is, he was brought there supposedly unconscious or stunned, and he was captured at some point while walking away from it and brought to the giant's HQ. At best, Steve would have no reason to believe Joe knows how to get to the camp, and several reasons to think Joe doesn't know.
When the camera switches to behind Logar and Betty as they face the first giant, they take on a purplish tint because of the blue screening used to put them in frame with the giant.