So if you mean a perfect game you really mean "perfect". Damn just that means hell if I'm in you're position.
And this isn't even the hard part.
The definition of a true perfect game (in my eyes) is as follows:
Being Able to Beat the Game
Have Yuffie & Vincent
All Characters Lv. 99
Have all Ultimate Weapons and Lv. 4 Limit Breaks
Have a Gold Chocobo
Have at least 1 of each Materia Mastered, including Master Materia
Have 4 Enemy Skill Materia's with ALL Skills
All Side Quests Done
Being Able to Beat Ruby and Emerald Weapons
Max Stats for All Characters
Gotten All Treasures
Have All Key Items Possible
Cleared the Gold Saucer
Have Max GP (10000)
Have Max Number of Every Item
Have 0 Escapes (f*** I ran from the Midgar Zolom once...)
Have a "Perfect" Chocobo
Max out All Characters' Natural HP/MP
Max out Experience and Gil
Max out Vincent's kills for Death Penalty (65535)
The list goes from least difficult to most difficult.