Character mistake: When fighting the Guard Scorpion in Mako Reactor No. 1, it says to "Attack while its tail is up!", using the "it's" as in "it is," which is grammatically incorrect. It should be "Attack while its tail is up!" with no apostrophe.
Other mistake: After you defeat Jenova-Life, it says "Beacause you are a puppet." "Beacause" should be "Because".