As the title says, I'm sure this sounds obvious enough in some way, but I think this is worth a mention.
With the final HP that Zeromus has at this point, he proceeds to cast Meteor... with a spell multiplier of 1. At the usual level that you are to beat him, you will be easily evading that spell... unless Edge is crippled in the magic evasion department or this is FF4A with Yang's awesome magic evasion stat. I had thought about this a little bit with a post regarding a "no equipment run" and came to the conclusion after taking a deeper look into his battle script.
If I ever get back to finishing my hack (I really need to), that sequence will not be that retarded.... as I think I've found a way to make it very... thought provoking.
We have EVEN MORE themes now, but some old ones are gone...