sorry if this has been asked before. currently, i'm in the temple of ancients and i realized that i didn't have the bahamut materia. i was told you receive it after you fight the red dragon. well, i didnt see it and just carried on. now i'm back in the mural hall and i can't find it anywhere. is it still there or i lost it for good? and this is right before the demon wall boss. ;__; also, any tips on that boss? i've died atleast 3 times in the past hour. any help would be great :)

Afaik it was only possible to miss the Bahamut ZERO huge materia, since you can screw that "quest" up. If you failed to pick it up however, it will be gone forever.

Demon wall becomes rather easy if you have anything like Haste and/or Protect Materia link with All. Makes the fight rather easy. Or level up a bit near a save point in the Temple.

Apparently, later in the game it's possible to dig up anything you may have missed at the excavation site in Bone Village (where you get the Lunar Harp and the Key to Sector 5 from), although whether that is indeed true or not I'm not sure.

If it is true however, I assume it would take a lot of fruitless digging before you finally 'hit paydirt' so to speak and find any items you missed getting the first time.

As for Demon Wall, if you'd taken the time to get Aeris her level 4 Limit Break Great Gospel, it makes that battle a cake walk. The Enemy Skills Big Guard and White Wind make it much easier too if you don't have Haste and Barrier materia.

The Bone Village thing is definitely true; I found W Item materia there after missing it in the return to Midgar.

Demon Wall is never difficult, wtf?

You really should be able to slap the wall around with Nanaki and Aerith, even Yuffie if u have her healing limit (clear tranquil right?) surely?
Just try to get full limit breaks on everyone before u enter the battle.
Besides, if you want quick leveling or quick materia masters, why not take ur bronco over to the edge of mideel, those little catepillar scythe things get u 400ap or something per kill and the sand worms are good for 5000gil.
(I have good knowledge of FF7, but havent played in 4years (stupid ps2) )