Quote Originally Posted by masamune1600
As raskerino mentioned, the NMSCIE challenge is among the most difficult and the most popular. Breaking it down into its component challenges can yield additional challenges of its own--it's possible, for example, to beat Emerald and Ruby while playing a No Materia game. Low level games and speed runs are also common challenge game approaches, although I disapprove of speed runs in general.

Really, there's no need to adhere to any preset challenge system; sometimes it's best to simply create your own conditions. You might try taking an NMSCIE component, for example, and also exclude Limit Breaks, or items, or non-elemental magic, or whatever else enhances the experience for you.
What he said. I've both done the NMSCIE challange and defeated Ruby+Emerald without materia.

The NMSCIE challange is indeed very challanging and overall a lots of fun... BUT sometimes you really miss the materia. It just feels too empty without materia somehow. So... it would probably be funnier (but also slightly easier) if you could use some kind of materia. You could play with either only magic materia or only command materia etc, if you want. But summon materia would make some parts of the game too easy since KotR and Hades are far too powerful.

The Ruby and Emerald without materia challanges are awesome. Emerald really isn't that hard at all. Just make sure to have the battle speed maxed or atleast almost maxed to make sure you'll be able kill him before the time runs out.

Ruby without materia is a "hell challange". It's probably the hardest challange there is in FFVII and it's VERY time consuming.