Well the level of difficulty in I is around the same as IV, if not easier. Also, there is not much character development (hell, they don't even talk). The story is well simple, like you said. It's just find A to give to B, get C from B, give C to D, etc... The battle system is alright (no ATB, which is good or bad for different people, it's a very normal battle system). The graphics and sound are good, esp on DoS and PSP.

I'll leave the rest to you. Hope I helped.