Minor things first, then a couple of weird ones.
1. Lying is right, as foul as it looks - don't let anyone tell you it should be lain, laid, laying, layed ...
2. When the killer blow has a side-effect, this is reported after the main event which looks odd.
"Fred kills Harry !" - "Harry is stunned !" (yes indeed) or "Harry resists !" (way to go, Harry)

3. When items are wielded in a slotted belt and the belt is taken off or swopped, the items are simply lost. This could have cruel consequences. It might be a bit kind to have them remain in the careless character's inventory, but think they should at least drop to the ground.
4. Scattershot's bunker-busting capability is not a bug, it's a feature ! ... call it rock splinters from the mighty impact.
5. The double-artifact thing isn't just confined to effects of stores. Found Sting in a room in the Vor Pride, left it at 'home' (another feature, though carrying capacity becomes so massive that's moot, is more a Mathom House really) and then found another Sting in the Vor Armoury.
6. ... where only the Athame was (if this is a plot twist ignore me, was square-by-square searched)
7. The description of Gloves of Criticals sounds as though it only affects spells, so for a long time didn't bother with the outrageous ones which were found - grr.
8. While using a hymn (detection, as a reward, just to have the black swirly effect really) it deactivated and then immediately re-activated on going between the two Level-Up windows. Can't imagine this has any game effect, just weirdness.
9. Okay, the weird one - could be symptom of something tricky - Emmanuelle's immediate predecessor died in the strangest way. She had gone briefly to the slime pits quite early on, and immediately came back out. When later on the level with the slime-pit stairs, the boss was beside them (quite far away) and being attacked by his own people - but also there were messages that my character was involved in the battle, folk taking some tiny darkness damage from the hymn. Got a message the boss was dead, went across and there was nobody there, just his loot. Returned there a third time, again there was fighting by the slime-pit stairs involving my character - who was actually ambling casually along a path with full health, and then suddenly died. It's as though a copy of the character was left at the slime-pit stairs, and indeed the death report said she was e.g. Level 37 (which she would have been the first time) rather than Level 43 (which she now was). Presumably she just stood there doing nothing (having no AI) and until my 'real' character entered the level, this was irrelevant.
10. Layout suggestion. Many folk have widescreen monitors, so vertical space is at a premium - better might be to have information strips at each side. The talents one would be okay, names aren't that long, but what about messages ? ... if this was on the left side, a nice code challenge would be that it's narrow by default "Fred hits the Or", but on mouseover expands to show the full story "Fred hits the Orc Pyromancer for 654.12 physical damage". Okay this would be awkward for starter-outers, or when the list has unscrolled itself - maybe a draggable frame that side for more casual reading ?
10b. ... or make Mt Doom run left to right

Seriously, there are so very few issues, sometimes trivially odd behaviour happens (e.g. saying that a category is now available for use, rather than a talent) but saving and restarting always clears such. Go back and read the praisey bit at the start again, it's 100% sincere, ToME 4 already is the state of this art. Speaking of art, the folk who do those tiles need big fat mithril medals.