The graphics of the PSP/PS4 version seem to be without a doubt worse than the PS1/PSN/360 version. The PS4 version is much more pixelated than playing the PS1 version as is the PSP version emulated to the same resolution as the PS1 version emulated. No matter what filters I use I can never get the PSP version to look on par or better than the PS1 version. This is especially noticeable on any in-game avatars and text, especially the Game Over screen. Visually the only thing I like about the PSP version over the PS1 version is that there are no horizontal bars in-game, but that's about it. There are also less visual effects in the PSP version.
Also, speaking of the Game Over screen, why was the PSP version based on what seems to be the original PS1 Japanese version that says "Let us go out the evening for pleasure" instead of the updated version that has the proper text, "Let us go out this evening for pleasure."? Kinda disappointed that they remastered/ported/whatever SoTN to the PS1 but everything about the port seems to be of lower quality except some bonus content, which doesn't include much. Outside of dialogue for Maria boss fight, there doesn't seem to be anything added that would require an entire redub. The new sound effects are distorted, at least in the PS4 version, the audio isn't properly balanced, just pretty annoying in general.
Then there's quite a few unexplainable problems in the PSP to PS4 port, such as the punctuation and entire lines of pixels missing from the screen at all times. I feel like the 2d entries have always got the shaft from a technical standpoint since... Symphony of the Night for PS1. Adventure Rebirth is an underrated gem as well IMO, but even that was designed as a 480p game which was obviously inspired and meant to look like a game designed on the Genesis. Not that it's a bad thing, but it's been 21 years and the PS1 version of SotN is still the best looking Castlevania game and IMO it has yet to receive a proper port to an HD platform(360's D-Pad is terrible and it's missing FMVs for the lamest reason possible).
Also, why in the hell can 360/One get the PS1 version of SotN but PS4 cant.