I'm running Arch Linux with Wayland. When I tried running the game as shipped by GOG, I only got a black screen and no sound. I tried to change settings or use windowed mode, but no success.

What did work was to download ags_3.5.0.26_linux.tar.gz from https://github.com/adventuregamestudio/ags/releases/latest and replacing the file ags64 and the lib64 directory in <INSTALL DIR>/game with the ones from the downloaded archive.

Afterwards, starting with ALLEGRO_MODULES=lib64 ./ags64 or the launcher script worked.

As "+1" would be too short some explanations - but the necessary information is already given above.

When starting the game on a fast AMD Zen2 Navi 10 system (Ryzen 5 3600 & Radeon RX 5700 XT),
the game shows really long a black screen (with Intel may be forever ;), then the music is disturbed
and mouse movements are slow.
The link above:
* https://github.com/adventuregamestudio/ags/releases/latest
leads now to the AGS 3.5.0.27 release and after swapping the directories lib64, lib32, licenses
and binaries ags64 and ags32, the game works perfectly.
I swapped by:
~~~
cd <GOG_INST_patch>/game
mv licenses orig_licenses_orig
mv lib32 orig_lib32_orig
mv lib64 orig_lib64_orig
mv ags32 orig_ags32_orig
mv ags64 orig_ags64_orig
cp -Rdpv <path_to_downloaded_and_un-zip-tar-ed_AGS_engine>/data/lib64 .
cp -Rdpv <path_to_downloaded_and_un-zip-tar-ed_AGS_engine>/data/lib32 .
cp -Rdpv <path_to_downloaded_and_un-zip-tar-ed_AGS_engine>/data/licenses .
cp -Rdpv <path_to_downloaded_and_un-zip-tar-ed_AGS_engine>/data/ags* .
~~~
What is striking is even the mere size difference of the binary:
Originally:
  ags64 2433744
  ags32 2511996
Updated versions:
  ags64 3467568
  ags32 3488596
~
The other AGS program I know of is "Mage's Initiation: Reign of the Elements",
which had similar problems solved via adapted start-script using:
    padsp ./game/ags64
(i.e. using PulseAudio's 'alsa-oss' emulation padsp -
which should be better solved with the method above using the current AGS engine).
I suddenly remembered and tested ... absolutely the same problem.
So should be fixed by the latest AGS engine.
~
So this update procedure should be done by GOG/developers for both games ...
May try to get this done - could be next year, though ... ;)