One of the most atmospheric games I've ever played, you
definitely need to give it a shot. It's easily in my top ten Genesis games ever, maybe even top five.
Yes, it is a "draw your own maps" kind of game; one of the characters has a spell which will show you a map, but it's impractical to use all of the time since it consumes MP.
Or, you could just go
here and print the maps out. Just be prepared to do some artificial grinding then; the game seems to have been balanced assuming you'd crawl every nook and cranny yourself, versus looking at a finished map.
If you have a Saturn, the sequel, Shining the Holy Ark, is an amazing game too, although with a
totally different aesthetic, having been done by Camelot versus the very small internal Sega team that did Shining in the Darkness (
one guy did 100% of the Darkness' design; Sega just threw a couple of artists and a programmer at him to help implement his game, then farmed out the music).
In Holy Ark, you can look at the map any time without having to use a spell.