Hello. It just dawned on me today how many games I have on GoG that don't function properly and I just want to understand whats going on. Okay so heres a list of examples:

Jade Emperor: had bad resolution when I ran it a year ago. was using a TV as a monitor. Now I have a monitor. Maybe I'll see if it looks better on this. Also may have had random crashes.

The suffering: Just randomly crashes

Silent Hill 4: Game works, but I'm unable to get the good ending because the game fails to spawn in certain possessions that I need to clear from the apartment.

Legacy of Kain Defiance: Controller doesn't work.

Other than that my 40 other games all seem to work properly.

Once a certain number of games are offered, it is no longer possible for any provider to guarantee functionality on all systems. Who could provide the hardware necessary for the corresponding tests? And that pure virtualization is not really a solution to the problem proves Microsoft with each of its updates.

Sometimes you just have to take things into your own hands to get a game running, e.g. by following the instructions on pcgamingwiki.

While I love when GOG makes a games work out of the box, it's fully impossible imo for every game to stay like that with ever-evolving hardware and software.

Sometimes even the, community fixes may not work anymore. If I were you, I would keep a backup folder with these fixes for games. I have a backup that contains several gigabytes of game fixes and troubleshooting guides I created in text file for both GOG and non-GOG games, as well as compatibility software that might need to be installed.

The suffering will need community patch to get running probably.

As Syphon72 said, it's just not possible. Although this information is already known and probably documented elsewhere, but in a recent interview (this one), those being interviewed effectively admitted (in summary, paraphrasing) that:
- The Q&A team that tests games is only so large, i.e. it only has so much manpower and can only test on so many systems, which cannot possibly account for all possible variance in user experience.
- Many games which were once tested and up to standard were found to be no longer so in some capacity (which may be down to increased standards of what is acceptable, or changes to modern Windows operating systems that renders those changes no longer sufficient)
- Only those on the preservation programme are currently receiving the care that would be required to ensure they are properly maintained for the future, and that this list of titles is at around 200 and set to increase to a target of 350 by the end of the year.
- A financial incentive (how much money a title will bring in) may be a reasonable indication of the amount of manpower GOG is either able or willing to assign to provide that title with the maintenance it might require. One might be able to reason, then, that financially profitable games may have an increased chance of being on the preservation programme.

As for those that aren't in the programme, well, hopefully they will get around to those at some point, but it's a never ending up-hill battle... so in a word - they're doing their best.

https://www.pcgamingwiki.com/wiki/Jade_Empire:_Special_Edition#Essential_improvements

https://www.pcgamingwiki.com/wiki/The_Suffering#Random_freezes

https://www.reddit.com/r/LegacyOfKain/comments/hhjq7o/controller_support_for_defiance_on_pc/

https://duckduckgo.com/?t=ffab&q=XPadder&ia=web

3 out of 43 doesn't seem that bad honestly.
I've run into worse streaks.
Just this past week I had three games that had some kind of problem ,( Not necessarily gog games, I can't remember what they were, could have been on steam or somewhere else)

Remember to check https://www.pcgamingwiki.com it often has fixes and suggestions and lists known issues with older games.

Which controller do you have?

By "controller doesn't work", do you mean it is not detected at all, or the controls are wonky?

I think Soul Reaver 1-2 and Legacy of Kain: Defiance (and probably LoK: Blood Omen 2) original versions have generic issues with modern X-Input PC gamepads, as those games were originally designed for old DirectInput controllers, and/or to be played with mouse/keyboard controllers.

However I guess Soul Reaver 1-2 don't have problems anymore as now GOG is selling only the remakes where I presume the controls are fixed for modern machines, but if you still try to play the original versions...

The option is either try to play with mouse+keyboard controls (can be quite painful), or use a third-party fix that fixes the controller controls, among other things.

Hmm, I don't see a mention of Defiance controller fixes in the PC Gaming Wiki page though... I do think I was able to get it to work ok with a 8bitdo XInput controller, was it then simply by carefully remapping all controls to my liking? I'll have to check if I had some fix files downloaded. I definitely remember there being such controller fixes at least for Soul Reaver 1-2, and probably Blood Omen 2, but now unsure about Defiance...

https://www.pcgamingwiki.com/wiki/Legacy_of_Kain:_Defiance

I was able to get good ending, so problem should be somewhere else.