It is a god damn weird game all around. I think the story revolves around Nakajima's summoning computer breaking and so you have to wander all over the maps in a semi-non-linear fashion to get the parts to put it back together? It's been a while. All I know is that unless you're like one of five Japanese collectors that actually thought to keep their manuals when that version of the game came out, you're gonna get lost basically as soon as the game starts unless you follow a wiki religiously. And even then the visuals are bad enough that you can still lose you way pretty easily. Interesting tangent when it comes to series history, though. Imagine what would have happened if THAT had been the successful version of Megami Tensei back in the day. ;D
One of these days I want to get a PC-88 just to try out all the weird and obscure Japanese games for it. At least the ones that aren't visual novels anyhow. >_>;