Mind elaborating on what makes the plot faceplaming? I'll admit that is isn't great, but it's still pretty good.
As one of this game's previous paladins, I'll give it a shot.
First, the idea that Dracula is weak and needs to gain strength is never fully realized because the game never gives you any real idea of when he's "powerful" beyond him no longer being a decrepit old man. At his peak, Dracula is supposed to be a being so powerful neither Satan nor Death dare challenge him, that it takes 500+ years for his enemies to get the confidence to re-invade the world. We never see this in the game, part for gameplay reasons and part for story reasons. For example, stealth. It makes sense at the beginning, but eventually it should go away. I think the first moment it truly becomes unacceptable is the Agreus fight, since you fight him right afterwards. There was no need for sneaking. It's pure gameplay reasoning getting in the way of plot. By the time he's put down Raisa Volkova, he should be able to bust Golgoth Guards like nobody's business. He's more powerful than a child of Satan, nobody but Satan or his other children should really be able to mess with him. And why is he sneaking into Nergal's headquarters? Why doesn't he just bring down the building? He logically has the power to do it, but no, he sneaks there and Nergal makes him his bitch with some lightning. Then, with no real upgrades after that, Dracula rips Zobek and new one and kills Satan. The game, story-wise, does a horrible job of making the player feel powerful outside of the actual boss fights. It's incredibly inconsistent.
Second, the castle cutscenes, while probably the best plot moments, never reach their conclusion. Marie gives him the most compelling speech in the game, about how he needs to free himself from the castle, become who she really knows he his, and choose his family, but it never happens. Dracula agrees with it, but it never really happens. To free himself from the castle, he needs to shed his dark side, since the castle is essentially a manifestation of his power, but this doesn't happen. Defeating Inner Dracula would show his dominance over his dark blood and his decision to move towards the light, but it doesn't happen. He fights Inner Dracula, but doesn't even get to strike the finishing blow. The blood just flows away saying "You can never get rid of me!", and it's right! As long as Gabriel is Dracula, he will never be able to live in peace. He will forever be stuck in the "castle" of his mind. He needs to die. He needs to find redemption in death. He wants to be with his wife. He does not want eternity, and Alucard doesn't either. Neither of them ever wanted to be a vampire, and while it makes sense that they could put aside their grudge to defeat Satan and Zobek, the idea that they just walk off into the distance as father and son is lame. You can claim that Dracula and Alucard's outlook on life just changed when they realized they had each other, but that's pretty weak and not really one of the primary themes of the story, and hence the claim of bad plot.
Third, Victor. His fight was awesome, but with what they did to him, he shouldn't have even been included. His shift from a hero of the Brotherhood and champion of humanity to buddy buddy with Dracula, the vampire that ruled the land with an evil fist, destroyed his order, and is the corrupted origin of his bloodline happens far, far too quickly. He literally gets handed the antidote, along with his butt, then makes up his mind to sacrifice himself for him. Even if we were playing as anyone else, the shift from "I am your enemy" to "I will die for you!" is way too fast. It's not even a spur of the moment Matrix dive moment. He pre-meditates sacrificing himself so that Dracula can
get an idea where the next acolyte is. He doesn't die defending Dracula from a badguy, he doesn't die trying to kill said badguy, he dies to become a glorified Dodo Relic. He completely ignores his responsibilities as commander of the Brotherhood. He also never gave that antidote to someone.
That. Is. Awful.
Fourth, a lot of the story is presented a very unique, psychological way. This would be fine if the game stuck to the series's themes of fate, vengeance, and redemption, but it doesn't so the story just comes off as a bunch of goofy head stuff and leaves a lot of loose ends. Why can the Vampire Killer kill Satan? It didn't kill him in LoS, so why does it work now? In fact, who says Satan is even dead? He didn't die last time, so why is he dead now? He was just sent back to hell. Same with Zobek. Zobek didn't die last time, so what makes him dead now? Nobody ever explains it. So if that's the case, then why did Dracula stage a 500+ year gambit for the sole purpose of killing Satan and Zobek if there is nothing in the game that tells us how this is actually going to finally kill them? The uncertainty of payoff to prep time ratio is untenable. And that's big stuff. There's little stuff too, like Dracula waking up, talking to Zobek, screaming, going back to sleep, then waking up again to remember his conversation with Zobek. The way it was presented is confusing. Or back to Victor, if Zobek can figure out that one of the acolytes is in the Biomek corporation, then why can't he conclude that the largest weapons dealer in the world that deals in weapons laced with dark magic might POSSIBLY have an acolyte in it? Victor needed to
die for that? Bad writing. They also tossed aside some primary themes, such as God's influence in the matter and the workings of Fate, with no real conclusion other than Gabriel smashing the Mirror and resolving that fate had no hold over him. But that was never the problem! The problem was that God revived Gabriel to repent, and Gabriel said "Fuck you!"
Now this is more personal preference, but the perfect ending to this game would have been something along these lines: Gabriel is ready to use the Vampire Killer on himself, but Inner Dracula doesn't allow it. He takes over Gabriel which ensues in a fight against Victor who gets the Vampire Killer and uses it to fight Dracula. Then, the fight would then flit between that and a mirror'd fight with a dark manifestation of Inner Dracula. So while Dracula fights Victor in real life, Gabriel fights Dracula in his mind. Then, Gabriel beats Dracula, symbolizing the letting go of his hatred and grief, and Victor uses the opportunity to impale Dracula with the Vampire Killer. Big impressive moment with light and blood and screaming and then bam, Gabriel dies and finds himself in the arms of Marie or something like that. That kind of ending would have utilized the themes of the series so much better.
I love Castlevania. I love Classicvanias and Metroidvanias. I've played every game in the series minus the gameboy ones. I love Lords of Shadow. Mirror of Fate is one of my all time favorite games, as little sense as that makes. I even give LoS2 a 7.5/10 because of how fun it's combat and boss battles were, and how beautiful the castle sections were. But I cannot get over how badly LoS2 botched up a perfectly set up storyline. It's just...bad.