Wrong: GOG is only working with the files they get.. They usually don't add or remove files. So if the puiblisher is uploading GOG files which do not work correct without Galaxy (something that is demanded with every GOG game) they need to fix the issue. The (obviously) client related file was not added by GOG, it was part of the build provided by the publisher. It is not GOGs responsibility to change files they get provided. It is their responsibility to tell their "partners" aboout it. I told Team 17 not just what the issue is but also how they can fix this and their reply was rather underwhelming. The fact alone that Team 17 knows about the issue without fixing it (they know this since at least a year) and therefore basically selling a knowingly broken game (if you take into account that GOGs games are supposed to be able to be played without any client) is borderline criminal.

You see it backwards. GOG is not even allowed to change files in the case of some publishers. So the NORMAL case is that the publishers are fixing their games and that they are responsible that everything is working as intended. Keep in mind that we are not even talking about examining the file in question ... everything works just after deleting the file in question so we are talking about the work of maybe 20 minutes or so ... depending on how long it takes to create a new installer pckage and upload it to GOG. Every publisher is allowed to upload things to GOG, only in rare cases GOG still wants to check those build before releasing it. Team 17 is a known publisher to GOG and you can be sure that they have free hand to upload their build through the Galaxy backend directly to GOG.

You really think the broken non-galaxy-savestate could have been be intended by the publsiher who wanted to sell their game DRM'd on a DRM-free store? Highly unlikeable (and I can't remember any other case in which such thing has happened here ... maybe Hitman but that was a bit different and the game was removed afterwards). Imo it is much more realistic that the publishers (or rather the devs) simply just tested the game with the GOG Galaxy client and neglected to test it without the client.

I have completed a couple of playthroughs in King of Seas, but non of the "Complete the game in xxx difficulty" achievements unlocked for me (I managed to unlock 24 achievements, only missing the 5 difficulty related achievements)

Anyone else ?

Can't help you with your question but I'd like to thank you for posting it. I did not even know that the game had achievements and since this obviously is the case the galaxy64.dll file now has a reason to exist if you use Galaxy. So for those who use Galaxy: if you delete the galaxy64.dll file achievements won't work anymore at all. This also means that for the game to be fixed completely in opposite of what I saidf (and tjought) before the galaxy64 file need to be replaced with a working one that won't break saving when not using Galaxy.