I played this obsessively back in the day. I love that there are so many viable ways to build your character and that most encounters can go sideways if you aren't careful, due to the debilitating status effects etc that some enemies can inflict upon you.
It can be frustrating at times, especially with ridiculously deadly hallucinations, but if you use all the items and spells at your disposal it's not unfair. I remember fondly discovering there was a secret cache of oil flasks near the first "boss" and if you loot them you can take him down to almost nothing by throwing them all at him instead of spending days grinding to get strong enough to fight him toe to toe.
The story is great, the descriptions are evocative, and it has both strategy and tactics. Highly recommend.
PS. the "cluebook" is actually a novel written as a story from the perspective of the main character and is worth the $10