Spectrum_Legacy: Now it's your turn. Please tell me how BLoodstained is compared to HK for example, since that seems to be our common denominator.
It sounds like Blasphemous might be the same subgenre of Metroidvania as Hollow Knight. Bloodstained, I would describe, as being in a different subgenre, one which it shares with Castlevania: Symphony of the Night (and the other Igavanias), Timespinner, and perhaps even Dust: An Elysian Tail.
Bloodstained has only manual saves. There are save points where you can regain your HP/MP, and have the option of saving in the save slot of your choice (and the game provides a lot of them, more than you'd realistically need, as I find that 1 slot per playthrough is enough). If you die, you get a game over screen, then a loading screen, then you are right back to where you just saved. You lose everything since that save, but nothing from before the save. (I far prefer this save system to Hollow Knights.)
Difficulty-wise, the game unfortunately suffers from a bit of an inverted difficulty curve. Normal is reasonable at the start, but it gets too easy later on. Hard is a bit rough at the start (the first boss is more difficult than a first boss should be), but gets manageable (though you still need to watch your HP) later on (excluding a certain boss who uses an instant death attack that appears to be undodgeable). Nightmare is even harder than Hard, and while I haven't played that much, is likely to remain difficult until you start getting the big lategame boosts and abilities. (I'm thinking that Nightmare might be designed for New Game +, to be honest.)
Aside from healing at save points, you heal by opening the menu, going to your inventory, and using a potion or food item. Each type of food also provides a permanent boost the first time you consume it. There are a few shards that appear later that allow for healing, but they tend to be weak (though maxed out Regenerate is nice).
The level cap, I believe, is 99 on Normal and Hard, but a typical player will reach about half that by end game. On Nightmare, you are capped at level 1, which is one reason that mode is much harder. You can also get permanent stats through food, as well as via the HP/MP/ammo max ups found throughout the game. (Ammo is used for guns; the first one is found early, but they do not dominate this game, plus you always have an infinite supply of weak bullets if you need them.) There's also plenty of equipment to find, buy, or craft in the game.
Also, enemies will sometimes drop shards, which provide you with various abilities, including MP-using attack spells and passive boosts. (Some shards, usually from bosses, open up movement options allowing access to more of the map.)
One thing to note is that the game has an extensive, perhaps too extensive, item crafting system. There is the nice fact that, once you've made an item once, it appears in the shop, but then the shop inventory gets huge later in the game, and money is scarce in the early game.
Classic Mode doesn't use 8-bit graphics, but it instead plays like the original Castlevania, except that you have most of the moves from Rondo of Blood's Richter (but no item crashes). There's a code to turn on 1986 mode, which restricts your moveset to that of Castlevania 1. The mode is about as long as the original Castlevania, and it's a nice tribute to it, and a change of pace if you're tired of the Metroidvania gameplay. (It's also a separate menu option.)