Ho boy, so here's the biggest culprit of "too much": Just how many goddamn modes you have to go through to unlock everything. Curse of the Moon had the regular mode, Nightmare Mode, and Ultimate Mode. Regular, you could go through with just Zangetsu, go through with a powered-up Zangetsu by killing the allies, recruit the allies along the way, or some combination of them. Beating Regular with all four characters unlocked Nightmare Mode, where you play as just the three characters, but the bosses are beefed up a bit and there are new routes accessible to you in the earlier stages. Then in Ultimate Mode, unlocked by beating a run where you kill all the allies, you get to play as Ultimate Zangetsu with the ability to recruit the allies again. It was a solid set of options that allowed for some leeway in how you played them.
In 2, you have "Episodes." Episode 1 is the main game, where you go through and the allies join you no matter what after the first three stages. Just like in the original game, though, you lose one of your allies at the end to demonic possession, leading you to Episode 2, which, just like Nightmare Mode, has suped-up bosses and a new final boss... but you lose Dominique this time, not Zangetsu. Dominique was the most useful character to me and this was where I used Casual mode, seeing as I had no intention of playing through the game with three, in my opinion, inferior characters.
Episode 2 has two endings. The first requires you to find the three hidden swords in the first three levels and combine them at an altar in the fourth, giving Zangetsu a new sword that cleaves demons but leaves living things unharmed. The second requires you to ignore these. After it was recommended to me by SomecallmeJohnny's review, I recommend you do the bad ending first... In Episode 1, Zangetsu receives a sword that makes him almost as powerful as Ultimate Zangetsu in the original. In Episode 2, you start this way, but if you combine the swords... you lose the abilities. An already-painful experience just got way harder. This is why you should do the bad ending first, since, unlike the first game, this game lets you freely return to older levels without losing progress.
The bad ending unlocks Episode EX, where you're given the new sword from the start. This route removes the new allies entirely, Dominique is still possessed, and now you play as the original game's cast of four. Since I played that game a lot and learned their intricacies, this made things a lot more comfortable for me. This was easily my favorite route. This one will give you the good ending of Episode 2 upon completion, which unlocks...
The Final Episode. This one's kind of neat. You have access to every level from the start, with every ally (including the rescued Dominique) recruitable. They've split up to gather materials, and picking their stage adds them to your party, which they become permanently added upon completion. Their distribution is apparently randomized. You can also pick up two powerups in every level, but their positions require taking different routes, which means... backtracking? In a Classicvania? Yep, it exists. Thankfully you can just leave the stage after collecting them, but it still gets kind of repetitive. This mode also gives you a fucking shmup segment and a brand new final level... with moon physics. In a Classicvania.
In Curse of the Moon, the final boss checkpoint had a free 1up for you to collect every time you lose one. So did the Episode 1 and 2 final bosses in 2. The true final boss of the Final Episode? Nope. Thankfully there's an easy exploit, using Dominique to jump and up-stab while tanking the attacks with the other seven characters to keep her alive. Otherwise, that's just a random and cruel change considering the other two final bosses extended that courtesy. I don't think the true final level wasn't that bad in comparison to the normal final level, but I certainly wasn't interested in going through it all again if I game over'd.
Hey, remember the true ending of the original, where Zangetsu somehow ends up in the future? Ignored. It's implied everything that happens in the original but Zangetsu's death and future reincarnation still happens, but that's it. Kind of a disappointment because I was completely on board with seeing what wacky concepts that could lead to, but I'm also fine with more classic Castlevania aesthetics.
But seriously though, people sleep on Alfred, the ice spell is OP in general and the fire spell neuters some of the more-annoying bosses.
Anyhow, there is one last mode to unlock... single-character mode. Done by completing the Final Episode as Zangetsu-only, skipping straight ahead to the final level, and beating it and the final boss with just this jackass. Count me out. If you beat Final Episode fully, you unlock the ability to choose Ultimate Zangetsu in any mode, which might make this more tolerable, but I'm still not enthused about the idea. And single-character mode is exactly what it sounds like: You play through the whole game as one single character. I have no intention, not even with Casual mode. That's too much effort and would wear me out way too fast. Also Robert is actual garbage and Alfred without a full party isn't that great either. Yes, I know I said his spells are OP, but you still need someone else to actually deal damage because his melee attack sucks.