During Aeris' death, you should have noticed Sephiroth's sword lacks blood when he stabs her. The reason for this is rather obvious... censorship. Square didn't add blood in fear of receiving a Mature Audience rating for Final Fantasy VII.

After Aeris' death Cloud sets her off for a burial at sea. However you will notice that Cloud is no where to be seen after he lets go of her. Cloud surley wouldn't have just let her go and turned away that fast. The water also appears to be atleast 8-10 meters deep, because Aeris drifts for a while. How did Cloud hold her and walk in the water? This was created to appease our thoughts for a beautiful send off. No doubt the final encounter of the two lovers would be expected to something we could all remember and feel inside.

A 'mistake' supposedly exists in the clock puzzle at the Temple of the Ancients. We all know the roman numeral representing the number 4 is IV. Well, in the game we see IIII in the puzzle instead. I've been told the ancient Romans had actually used IIII to represent 4, and it was only changed to IV during recent times.

Some people have reported Red XIII's cubs in the ending sequence were added by mistake. However, there is actually a real reason for this. Recall Bugenhagen's death? Before he dies, he says to Red XIII,

  "It's a wide world and you must go out and see it... You may even find your life's mate. You never know."

  Bugenhagen hints other members of Red XIII's species exist somewhere in the world. Hence, Red XIII has a mate to make cubs for the ending sequence.

A spelling 'mistake' exists in this particular screenshot. Click on the left thumbnail, and glance at the text on the car's door. You'll read "Midgal's Motor Group".

Remember finding Tseng in the Temple of the Ancients. Aeris says "...Tseng's with our enemy the Turks, but I've known him since we were little...". However, this is a contradiction with what we see earlier in the game, when Elmyra recounts Aeris' childhood. In this particular scene, we see Tseng in Aeris' house, demanding Elmyra to give him the child. Tseng is clearly an adult, so how can Aeris say she knew him when they both little!?

Glance at the first screenshot of Sephiroth. Notice he has no gloves. Now peek at the lower screenshot, and you'll discover he has gloves. Somehow, midway through killing Aeris, Sephiroth managed to gain gloves for no reason at all!

After Aeris is killed by Sephiroth, we see Cloud lifting Aeris with her head to Cloud's right (and her feet to his left). However, when we see Cloud dropping her into the lake, Aeris magically changes orientation. Her head is to Cloud's left and her feet are to his right.

During Cloud's Nibelheim flashback, a FMV sequence is shown of Sephiroth finding Jenova. Jenova's face is displayed up-close. What is peculiar about Jenova is she's wearing a metal helmet. On the helmet is a plate inscribed with English words.