These are the PSP ports of Rondo of Blood and Symphony of the Night that came bundled with Castlevania: The Dracula X Chronicles on the PSP. Supposedly, they run on the PS4's own PSP emulator, which is why this collection never got ported anywhere else: because it isn't actually a port.

It's also why it's pretty barebones, with no extras, save states, rewinds... It doesn't even include Dracula X Chronicles itself. It at least has trophy support, and the trophy list for SotN showcases a lot of nifty stuff about the game. It also, surprisingly, has no input lag that I could notice: everything runs pretty smoothly and responsively.

Well, there is one huge issue, which is that moves that rely on d-pad button sequences, such as Alucard's spells and most of the special moves for characters in both games are incredibly hard to pull off in this version, apparently due to a change on how inputs are handled that requires extreme precision and timing. This changes how the games are played: spells are now an unreliable mechanic, moving around with the bat is sluggish, and Richter mode in SoTN is infuriating.

I'd say if you get it on a sale, and you're aware of the aforementioned issue, it's worth it for SotN alone. But I do think the collection could have been done better.