Teseng did die cause elena said somethig about you killing her boss before she trys to slap you. but you are right he is in advent children.
The tatoo was put on red by Hojo remember some one said how many guys were there with the numbers and red said the Hojo put the number 13 on him so there must be at least 13. In the hunted house at the golden sauser.
When you see sephiroth for the last time his face is covered in bloud.
here are some more mistakes taken from www.ff7citadel.com
During the seen where aries dies notice he has no gloves. Now he has gloves. Somehow, midway through this FMV, Sephiroth managed to gain gloves for no reason at all!
Tseng's Age 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!?
Cathy Okada's translation of this line from the Japanese version of the game (go here for the full list of her translations), which reads, "...Zwong (Tseng) is a Tarx (Turk)... he's the enemy but I knew him since I was a child." Note the "I" in Aeris' words, which explains why Tseng would be an adult in Elmyra's story. Chalk this one up to another mistranslation...
Aeris' Position
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.
Ropeway Propellers
When you visit the Gold Saucer, the propellers on the cable car change position during your first visit the gold sauser.
Lettering on Rocket As the Shinra No. 26 launches into space, a close-up of the rocket momentarily reveals that the lettering on its side ("Shin-Ra Type 26") has been flipped!
Altar Staircase
When we first see Aeris at the altar, she is facing the stairs, with her back to the railing. However, when Sephiroth comes down with his sword, both he and Aeris have their backs to the stairs. Once the FMV ends, they are again facing the stairs.
The Sister Ray's Misalignment
No screenshot available When the Sister Ray is fired from Midgar, it destroys the barrier over the Northern Crater. However, if one flies (in the Highwind) from the cannon in a straight path toward the Northern Continent, they will miss the crater by a number of degrees.
That Diamond WEAPON might have redirected the Sister Ray's shot is unlikely, since the related FMV shows the shot going straight through the WEAPON, without changing direction (there's also the matter that Shinra wouldn't have planned for the WEAPON's presence).
What doesn't constitute as an error?
The following 'errors' actually aren't errors at all. Rather, these have been added by Square deliberately.
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.
During Aeris' death, you should have noticed Sephiroth's sword lacks blood when he stabs her. The most likely reasons for this are censorship, technological limitations, or both. Square didn't add blood in fear of receiving a Mature Audience rating for Final Fantasy VII.
An alternative theory has been provided regarding the properties of the Masamune blade. Click here to read.
This third 'error' is grey. You should have noticed that Cloud isn't anywhere to be seen after dropping Aeris. Surely he didn't withdraw himself that quickly from Aeris' body to completely disappear from view. Secondly, by judging the camera depth, the water must be at least 10 metres deep. How did Cloud manage to walk in such deep water while holding Aeris?
I personally believe these oversights were deliberate. It would have damaged the romance of Aeris' death had the laws of physics been obeyed.
(If the laws of physics had been obeyed, we would have seen Aeris floating in only 1 metre of water, and Cloud would have casted an imposing shadow, ruining the majestic halo around Aeris.)
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.
these had to be slight ly changed as it was refering to screen shots which i could not copy but go to www.ff7citadel.com to see the whole thing.
oh and il take back the thing about Red being the only one of his kind. sory