If you're interested, there are a number of features that can be unlocked in FF7PC... providing you're good enough to get down to the nitty-gritty and hack through the main EXE. What I'm going to give you is the features themselves... but I have no idea how they can be unlocked. I only know of their presence. (But note that anyone who manages to do this will probably have their praises sung far and wide....)
1. Misprint: Materia that add to Magic Def actually add to Spirit, like they should do; this is a mis-labelling of Materia abilities.
2. Bug: Magic Defense is not used at all to determine battle mechanics defense against magic. Only the Spirit value is used. Thus, any piece of armor that adds to Magic Defense gives *NO* benefit whatsoever.
3. Forgotten Feature: Every weapon in the game has an element out of the following: Cut, Hit, Punch and Shoot. Shoot is probably facilitated only to demonstrate Long Range ability, but the other three have no seeming use at all, even though a few enemies list weaknesses against them (Desert Sahagin are weak vs Punch). These weaknesses do not work, that I've seen. (In addition, the element names should really be something like Edged, Blunt and Pierce, or something similar; the current names are misleading)
Those three challenges should be enough. They're listed in order of difficulty (though even (1) should be reasonably tricky to fix, unless you know your code). Just thought it was worth bringing these to your attention, is all.
Have fun.