How is it loose? Because it includes characters that are not in the pretty much story-less 2D action game?
I was honestly surprised by how well they were able to tell a story based on what little of a premise we actually get in the game.
OK, so I'm watching this silly argument being thrown around TOO much to keep quiet. It's been literally three days of Castlevania fans spouting this nonsense nonstop, all over the internet, looking for an excuse to diminish the games' lore.
Castlevania III doesn't have "so little premise" nor it's "pretty much story-less". It actually is the one of the games with the most plot on the NES which, while not hard of a feat to pull off, IS a feat in itself considering how little plot non-RPG NES games had. The adaptation on Netflix IS very loose in consideration of the original story. And that's talking only of it alone -- not counting expanded plot given by further games or media such as SotN, Judgment, Curse of Darkness or the Manga.
"Speakers"? Not in the game. "Sypha has a family"? Not in the game. "Trevor's excommunication"? Not in the game. "Church representatives oppresing people"? Not in the game. "Legendary sleeping savior myth"? Not in the game. "Dracula giving people one year to leave"? Not in the game. "Castle is special because is some kinda machine"? Not in the game. "Mystery prophecy about who will kill Dracula and with whom's help"? Not in the game (and this last one possibly killing Grant as one of the four warriors). And here I'm talking only of stuff that is directly stated to not be the case on the original plot itself, or that changing something would change the original plot's essence. I'm not talking about shit that expanding on the animation would have little to no impact on the original story, such as Dracula acting as a human by behest of Lisa.
Some of this stuff contradicts
directly the original plot to the point of unrecognizability. Sypha being a Speaker flies in the face of her origin story given on the manual, and is completelly opposed to her final resolution as an operative of the Church whose failure prompted the Pope to seek a Belmont. Prophecy talking of "A hunter and a Scholar" overrides completelly the reason why Alucard hid and who are the final warriors to stop Dracula. Will these work on the show? Good. The original game has enough storyline that causes these changes to be incompatible with the original lore.
So, yes. The Netflix show IS very loosely connected to the actual CVIII plotline. You want to praise the show? Of fucking course you're allowed to do it,
including praising the new plot. Just don't say "CASTLEVANIA HAS NO PLOT! THEY DID A MIRACLE WITH WHAT LITTLE THEY HAD!" because there is zero miracle involved, and there's a lot of original plot to be worked with. "Castlevania has no plot" is a meme by people who were raised with the US manuals, where the actually-quite-complex-for-a-simple-game plot has been reduced to complete bullshit nonsense, and not actual fact of the Castlevania franchise.