The Fireshadow is added by TFix (as many other things, such as the "little big world" section in The Sword) also to the original (Dark Project) version of the game. It is of course an improvement but in a way it is a sad aspect that the original version of the game "as it was" with all its little differences (both gameplay- and engine-wise, sometimes intertwined ) is not playable on modern setups in any way anymore. For example, how many players today know that you could get enemies drown ...
I have no axe to grind here but I think you're being slightly unfair to it (definitely in rating) by overfocusing on an aspect or two of the mission and disregarding the whole rating picture. This was arguably the second best mission of its era and I think what most players liked about it was precisely that being caught offguard after a seemingly another dull dour (not so, there are fineries) run-of-the-mill mansion heist by the depths and lengths it went into, with pretty even and strong pe...
To me also it's actually a 7.5-7.75/not a straight 8 due to the slightly repetitive level design/assets/secrets approach and no surprises/unique situations of any kind but still a clear step forward (not least in overall conciseness) from Into the Dark Forest Rem. where some parts of the map were just entirely redundant run-throughs (and there's again no shortcut of any kind to get back to the start once all is done but this time it's at least less gross given the slightly more manageable mis...
Kept Away From View: just follow the courier, erm rogue, erm keeper* (*according to campaign authors).
The transformation in the library could have had some real impacts in the campaign, as it is it feels ultimately very self-contained (and references to something that plays far after the originals should have been kept to a minimum) - that and the weirdly mechanical feeling about the sanctum's layout and (far too regular) geometry, as if made first using an automated tool and the rooms ...
There's not just a sword (blade) with holy weapon and other interesting properties you can get easily in this (2nd) mission but also and notably a very complicated, cool & awesome scripted procedure (with an equally cool guide) to get an even more potent AoE (mostly) one-shot weapon against the undead (with limited charges so to be used wisely), one of the ingredients for which also functions as a "sort of" funny lesser weapon, in addition to several holy water potions, one of which again in...
It's a shame you haven't played Calendra's Legacy first. That's the Source.