At the mission briefing, Casey calls the diethyl ether compound as
"C-2-H-one-twenty" while the bottle is labeled "(C2[space]H5)[space]2O" (all numbers being subscripts, the last character being the letter O). What's more, the label as written is gibberish. There should be no spaces at all in the formula, so that it should be written as (C2H5)2O (with all numbers being subscripts). Apparently Lynda Day George thought that ") 20" should be read as "one-twenty".
Barney rigs Collins' radio with a tape player so that when he turns on the radio he will hear a report of a possible war breaking out. When Collins turns the dial he finds other, different, reports. This would be impossible without multiple tape players.
There were two problems with the staged nuclear strike. The first was the sound of the incoming missiles - ICBMs travel at supersonic speeds, meaning that they would reach their targets before the sound of their shock wave would arrive. The second was the flash and Collins' reaction to it. As a scientist working with weapons-grade fissionable material, he would have known that by looking at a nuclear explosion with the naked eye he would have been permanently blinded, and the fact he wasn't blind should have let him know something wasn't right.
The IMF team places makeup on Collins' face to make him look older and he is not aware of it. Anyone who has ever worn facial prosthetics, such as he is wearing, would know they are wearing them.