well it kinda figures that it will take up way more space because it is showing more than 2 dementions, to make a proper RPG (one that lasts at minimun 40 hours even to the designers) you'll need 3 or 4 diskes, that's why Finla Fantasy VII, VIII and IX all had 3-4 diskes, or you can just use 1 DVD Disk as used for X, X-2 and XII, but it wouldn't be too hard to make the resorces, music and sounds should be easy, your nomal MP3, OGG, WAV, MIDI, but tilesets would be s differnt story but characters, i know of a program what can make 3D Models, it was used by all the kids in my high school to make custom models for Half-Life, but then mostly everyone went for the fully naked and visible girl and not their own (i ended up making one of D and i used him all the time), as far as i know, all you need to do to the program is chnage some options in it to make models for any game, although i lost the copy i had when i got Roll and i must have forgotten to trsnafer the installer, and i wouldn't dare transfer it now cause of a virus on the old computer and i'm not infecting Roll
for just the picture, i don't know what kind of battle system but with what i can see, i don't think it's ATB