I currently am playing
MM but I don't see how it is very dark. I mean, yes, the moon crashing into Termina is sort of dark but
TP is way more gloomy. Yes I know this topic is not about "omg I can't see" situations, but think about it. When you were Wolf-Link roaming around in Kakariko you cannot say that's not dreary. Seeing Renado, Barnes, and the kids all huddled together, scared of the shadow beasts was much darker than a poisonous swamp (which
TP also had. Remember when the monkey stole your lantern. Yeah, there). And the whole City in the Sky deal, the Oocca's city being ravaged by the Kargoroks and Argorok is dark, although the dungeon is bright and airy. Almost all of the Zora's died, the Gorons were in panic due to the loss of Darbus, the Kokiri, Gerudos, and the Sheikah were wiped out (except for obviously Impaz, and in the Gerudos case, Ganondorf). That's why I voted
TP as the darkest as opposed to
MM.