Battle Square: it says "Off Course!" when it asks if you want to fight, instead of "Of Course!"

Obvious Aeris one: "This guy are sick."

Midgar G-BIKE FMV: when you see aeris and tifa in the truck that you protect in the very first g-bike mini game, it says "Midgal" instead of "Midgar" on the side of it. Probably because Japanese can't pronounce their "r"'s

Aeris' Death: When Cloud carries Aeris to the little body of water, Aeris' head is on Clouds right, but then her head is on Cloud's left in the screen right after. she magically switched her body position O_O

Also, apparently this isn't a glitch but Square did it on purpose: Cloud stands in the water while carrying Aeris, and then Aeris drops down deep into the water, without even seeing Cloud on the surface, or even a shadow of his. how did he float?

Shinra Rocket: When they launch the Shinra No.26 into space, and you see the FMV, the whole logo "Shinra No. 26" is completely flipped around.

I didn't actually discover these tho. so i won't take credit. The site that i got these at is http://www.ff7citadel.com/secrets/s_errors.shtml . Credit is given here to those who discovered it.