Continuity mistake: When Guile infiltrates the base, he has as his only weapons a pistol and a couple of knifes. But when he fights the Bison troopers in the control Center, he suddenly has a Heckler & Koch MP5 submachine gun. He does have the magazines when he enters the lab, but the submachine gun is fairly bulky and thus should be visible when he comes in.
Continuity mistake: When everybody prepares to bail out of Bison's base, Honda and Zangief are still locked in combat; Zangief is wearing an undershirt. But when Honda breaks away, the shirt is suddenly gone, and there is no indication - including tatters - that is was ripped off during the fight.