These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Critical Research Failure: The GURPS book, set after Soulblighter, has several references to The Deciever fading into the background and refusing to share information after the battle with Shiver. That's probably because he died in that battle (see Taking You with Me).
The Trow iron warriors in Myth III. Remember how the Trow in the first two games were capable of killing several of your best units even when surrounded, were too fast to outrun, but only showed up in small numbers so it was a fair challenge? These guys are kind of like that, except armored like a tank and carrying a Big Freaking Hammer, which liquefies several units with each blow. They also have a ton of HP and don't turn to stone until it's fully depleted. You also have no special abilities or giant units of your own to counter them. They frequently come at you in pairs and there are levels with more than ten of them. Ironically, the only way to beat them is to exploit the equally broken AI, which doesn't realise that Trow now move, turn and attack too slow to ever catch or hit some units and will gladly run in circles after a lone Heron Guard while your archers and dwarfs rape them ever so slowly. Worst of all this is how the developers intended you to beat them. Way to completely take the fun out of the game.
The Tain makes fighting meaningless, though it only lasts for half a level. Why it's not used again later is anybody's guess. It is so overpowered that the rest of that campaign, after the only enemy that can counter it is dead, happens offscreen.
The Tain isn't used again because it summoned an army of mind-controlling extra-dimensional spiders that the Dwarves who created it died to stop.
Narm: Myth III often lapses into this thanks to some hammy voice acting in contrast to an otherwise fairly dark and serious story and cutscenes that feature characters making silly gestures and not moving their mouths while speaking.
They Changed It, Now It Sucks: The main complaint about Myth III, aside from the horrendous number of bugs, was that it just doesn't feel like a Myth game with the perspective switch from the desperate average soldier to the fearless conquering hero. The goofy looking cutscenes and drawings, bland level design and addition of magic-users from races that weren't supposed to have the intelligence for it didn't help either. Turning the Trow from the iconic fast and deadly juggernauts into completely brokensluggishretards and then making them the main enemy for several levels in a row was the last straw for most fans.
Cronus' death is painted as very tragic: a man who went paranoid about losing his throne to the point of negleting his children and losing the love of his life, Rhea. His last moments are him musing how Gaia will not take him back and won't be reunited with Rhea in death. Many readers can't help but pity the guy.
Cronus' brothers only remained by his side and aid him control the world because they believed that, with time, the Cronus they used to know would return. After realizing that their little brother would never return out of the crazy overlord he become, all of them stepped out of Zeus' way.
The whole Olympian siblings. Their dad got insane, Hades was forced to kill his mom, Zeus watched his mom being decapitated, the rest of the sibling were trapped in crystals by their father. After the war, Zeus lost his first love, declared he would hate Hades forever (and take note, Hades was his favorite brother) and now has a whole world over his young sholders. Hades is hated by his little brother and exiled and he's fine wih it because he considers Zeus' hate will make him strong. Poseidon suffers for seeing his brothers suffering like they do, Demeter only gets to see Hades once in a while and then dies. Rhea is kinda of a Love Martyr under her Clingy Jealous Girl exterior and Hestia, despite being the second older sibling can't do much to help her younger siblings but provide them a place for solace.