I played through it with a friend and actually had a good time throughout. I found the atmosphere, puzzles and dialog mostly good and entertaining. Gabriel is deliberately written as an arrogant womanizer, but he does have something of a good heart somewhere. I really liked Grace, as she was able to stand up to him well, as was Mosely. The game was much longer than I expected but maybe we were just being dumb^^ Some of the puzzles were really stupid (like the one with the vine or some of the voodoo code puzzles...DREI DRACHEN^^) but all in all it's a good adventure experience.

In my review of the original Sins of the Fathers I explicitly mentioned the strength of Jane Jensen’s script as the defining core of the game. This remake being faithful to that, it inherits this particular strength from its predecessor. Its differences in art, atmosphere, design and voice-over on the other hand make it clearly inferior to the original. Its few positive changes might still be an argument for some players to rather play this than the original if they simply cannot do with the pixely/old-schooly-ness (that's a word, right?). To not repeat myself in this review, I’ll just mention the positive and negative changes I noticed:

The Good: The new interface is a change for the better; the context menu makes interactivity easier. The inventory menu now highlights items that can be more closely examined or combined. The higher resolution plus new 'view angles' for some shelves, tables, etc. also let you examine stuff more easily and add more detail. The map is accessible from anywhere, meaning that you don’t have to walk to an exit every time. These are all welcome quality of life changes. One other positive change is the interior of the castle hall, which is now more realistic and closer to the sequel's depiction.
There are also some new additions: There is a new scene added later in the game at the police station, which is cool. The prequel comic for Sins of the Fathers that was shipped with the original game‘s box is now accessible from the main menu. It explains the background of what is going on in Gabriel's dreams. You don't have to read it before playing the game, in fact, it might be better for the mystery if you don't because Gabriel only gradually learns about his family's past.
At every location in-game you can access a newly added menu which shows the original sketch for that location and the look from the original game. Interviews and comments from the original developers were also added. (Have I said 'original' enough times?)

The 'meh': Very few puzzles are slightly changed but it's not detrimental. Some puzzles were added and feel weirdly out of place. I don't think they're completely bad, just unnecessary. Then, the music: The sound quality is undoubtedly an improvement. But, and I am biased here loving the original OST so much, the arrangements are a bit hit or miss. Some I really like, some are worse because they lose the atmosphere of the original - compare the vooodoo museum track: old vs. new - which is a problem of the game itself and therefore I won't judge the music for that; it has to adapt to the new style. I just prefer the more synth-y feel of the original.

The Bad: I'll start with a nitpick, but why roll the credits after the initial nightmare sequence? It hurts the pacing and is just such a weird way to start the adventure. With that out of the way, onto the heavy stuff: The characters' animations are not so great. They take too long (being not as fluid as the 2D sprites) which makes certain actions they take annoying. They can also suddenly change their pace while walking or make awkward gestures while moving. They feel weirdly outdated, but that's probably due to the budget. The animated character portraits during conversations are also weird, some of them having outright dead eyes. The faces are sometimes a drastic change from the original… They also replaced some scenes which were originally created in-game with more comic panels (these being used in both games for important cutscenes) and removed many incidental movements to cut extra animation.
The biggest change is rooted in the initial idea of making the remake episodic (ugh): The game is more linear than the first, with the intention of giving each day the same amount of content. Even disregarding that the non-linear approach was so good in the original, this new design makes no sense in some scenarios. Without spoiling, there is a character you now 'have to' find and figure out how to talk to, but can’t advance with further because you lack information you gain on another day. It also affects the hunt for specific clues, with one clue obtainable when you don’t need it anymore. This makes the new structure feel artificial, as well as frustrating for returning players. Though it may make some puzzles easier for newcomers, I doubt that clicking on several locations only to learn that they are 'closed' at the moment is very inviting.
The new voice actors are… okay. They are generally a good fit for the characters. But they just don’t compare to the original cast, e.g. in regards to nuance, charm and personality.
The new backgrounds, and the lighting especially, are much warmer than the original. And, in some places, also more drab - some comparisons here. It’s a completely different atmosphere that, of course, changes the tone for the whole game. It has less of a distinct 'look' and just isn’t as nice as the original - higher resolution or not. It also makes the supernatural stuff feel less realistic by not reflecticing the gothic nature of the story appropriately.

In summary, while the remake offers some quality of life changes that can be genuinely considered positive, the overall presentation and forced linearity are too much of a change for the worse. This also applies, but less harshly, to the new voice-over. The 20th Anniversary Edition feels too different and loses so much of what made the original truly special, with these design decisions not making it have a solid identity of its own, either.