...ok...you don't count...lol.

Better yet, you have to beat sephiroth at level 50 without omnislash or KotR or using any of the following materia:

All Offensive Magic Materia
Phoenix Summon Materia
Quadra Magic Materia
Mime Materia
Final Attack Materia

Everything else is open for use...Except Gameshark.

I didn't use any of those either!!!

Do I still count?

Nore did I, nore many many others....it's no challenge.

However the one Toothache is suggesting is pretty interesting.

I have done a 'Jobs' playthrough, where you only equip Materia that suites or would make up a paticular characters Job Class. Not so much a challange, rather just a more intresting take on the gameplay, but it does make certain parts of the game harder considering the fact you don't have everything open to you.

I have never ever to this day worked out how to get that, any help?

Win battles until the last 2 digits of the total are the same (eg. 233, 344, 799 etc...) and talk to the sleeping man in the isolated cave near Junon (you will have to use the buggy to get there). He will either give you a Bolt Ring or some Mythril. Get the Mythril and take it to the Weapon seller near Gonganga (the guy who sold the Keystone to Dio) and he'll give you a choice of choosing something from the big box or the small box. The big box has a Gold Armlet inside and the small box has the Great Gospel item. The best time to do this is obviously after you obtain the Tiny Bronco but before you obtain the Keystone from the Gold Saucer.

too late, ive already gotten my characters to lvl 99. and mastered the materia i use.

LOL holy crap, good luck with that man. seriously, you will be the man/woman(if you're a female) if you can beat the game with those stipulations.