I've installed the necessary 32bit libraries, here it is the ldd output

linux-gate.so.1 (0xf7796000)
libdl.so.2 => /lib/i386-linux-gnu/libdl.so.2 (0xf776c000)
libpthread.so.0 => /lib/i386-linux-gnu/libpthread.so.0 (0xf774f000)
librt.so.1 => /lib/i386-linux-gnu/librt.so.1 (0xf7744000)
libGLU.so.1 => /usr/lib/i386-linux-gnu/libGLU.so.1 (0xf76c9000)
libGL.so.1 => /usr/lib/i386-linux-gnu/libGL.so.1 (0xf7665000)
libX11.so.6 => /usr/lib/i386-linux-gnu/libX11.so.6 (0xf7517000)
libXcursor.so.1 => /usr/lib/i386-linux-gnu/libXcursor.so.1 (0xf750b000)
libm.so.6 => /lib/i386-linux-gnu/libm.so.6 (0xf74b6000)
libgcc_s.so.1 => /lib/i386-linux-gnu/libgcc_s.so.1 (0xf7498000)
libc.so.6 => /lib/i386-linux-gnu/libc.so.6 (0xf72e1000)
/lib/ld-linux.so.2 (0xf7798000)
libstdc++.so.6 => /usr/lib/i386-linux-gnu/libstdc++.so.6 (0xf7167000)
libGLX.so.0 => /usr/lib/i386-linux-gnu/libGLX.so.0 (0xf7144000)
libGLdispatch.so.0 => /usr/lib/i386-linux-gnu/libGLdispatch.so.0 (0xf70e4000)
libxcb.so.1 => /usr/lib/i386-linux-gnu/libxcb.so.1 (0xf70b6000)
libXrender.so.1 => /usr/lib/i386-linux-gnu/libXrender.so.1 (0xf70aa000)
libXfixes.so.3 => /usr/lib/i386-linux-gnu/libXfixes.so.3 (0xf70a3000)
libXext.so.6 => /usr/lib/i386-linux-gnu/libXext.so.6 (0xf708e000)
libXau.so.6 => /usr/lib/i386-linux-gnu/libXau.so.6 (0xf708a000)
libXdmcp.so.6 => /usr/lib/i386-linux-gnu/libXdmcp.so.6 (0xf7083000)
libbsd.so.0 => /lib/i386-linux-gnu/libbsd.so.0 (0xf7067000)

but when I try to run the game this is what I get:

Running Shadowrun Hong Kong - Extended Edition
Set current directory to /opt/GOG Games/SHK_EE/game
Found path: /opt/GOG Games/SHK_EE/game/SRHK
Aborted
It seems Shadowrun Honh Kong has exited unsuccessfully (error = 134).

What else is still missing?
Any help would be appreciated.
Thanks in advancce.

I'm not sure, but I think that gog's start.sh script includes their own directory with supplied libraries into the library path. Have you tried running the binary directly? That's what I do. Normally I would suspect a libstdc++ ABI mismatch, but the game works fine with my distro's latest libstdc++. In any case, the best next step would be to run the game in gdb, and do "thread apply all where" to see where it crashed.

Yes, you're right, but for some reason the game cannot find them by itself, so I had to install those provided by the official repository.

This is what I get using gdb:

Starting program: /opt/GOG Games/SHK_EE/game/SRHK
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
Found path: /opt/GOG Games/SHK_EE/game/SRHK
Mono path[0] = '/opt/GOG Games/SHK_EE/game/SRHK_Data/Managed'
Mono path[1] = '/opt/GOG Games/SHK_EE/game/SRHK_Data/Mono'
Mono config path = '/opt/GOG Games/SHK_EE/game/SRHK_Data/Mono/etc'
[New Thread 0xf6d86b40 (LWP 3083)]
[New Thread 0xf6d55b40 (LWP 3084)]

Thread 1 "SRHK" received signal SIGSEGV, Segmentation fault.
0x088ae120 in ?? ()

not of great help, in my opinion

After that, type "thread apply all where". That will give more information.

For example, if I add gog's libraries to my LD_LIBRARY_PATH, the game crashes with a segmentation fault, and says:
Thread 1 "SRHK" received signal SIGSEGV, Segmentation fault.
0xf7fe270c in _dl_relocate_object () from /lib/ld-linux.so.2
(gdb) thread apply all where

Thread 3 (Thread 0xf6d6db40 (LWP 5599)):
#0 0xf7fd5b49 in __kernel_vsyscall ()
#1 0xf7f46fce in do_futex_wait.constprop () from /lib32/libpthread.so.0
#2 0xf7f470cf in __new_sem_wait_slow.constprop.1 ()
from /lib32/libpthread.so.0
#3 0xf74e2b81 in mono_sem_wait ()
from /mnt/games/Shadowrun Hong Kong Extended Edition/SRHK_Data/Mono/x86/libmono.so
#4 0xf743f488 in ?? ()
from /mnt/games/Shadowrun Hong Kong Extended Edition/SRHK_Data/Mono/x86/libmono.so
#5 0xf74b04f1 in ?? ()
from /mnt/games/Shadowrun Hong Kong Extended Edition/SRHK_Data/Mono/x86/libmono.so
#6 0xf74da527 in ?? ()
from /mnt/games/Shadowrun Hong Kong Extended Edition/SRHK_Data/Mono/x86/libmono.so
#7 0xf74fc016 in ?? ()
from /mnt/games/Shadowrun Hong Kong Extended Edition/SRHK_Data/Mono/x86/libmono.so
#8 0xf7f3c6d2 in start_thread () from /lib32/libpthread.so.0
#9 0xf7b61cf6 in clone () from /lib32/libc.so.6

--Type <RET> for more, q to quit, c to continue without paging--
Thread 2 (Thread 0xf7f99b40 (LWP 5598)):
#0 0xf7fd5b49 in __kernel_vsyscall ()
#1 0xf7f4908b in nanosleep () from /lib32/libpthread.so.0
#2 0xf74c46df in ?? ()
from /mnt/games/Shadowrun Hong Kong Extended Edition/SRHK_Data/Mono/x86/libmono.so
#3 0xf7f3c6d2 in start_thread () from /lib32/libpthread.so.0
#4 0xf7b61cf6 in clone () from /lib32/libc.so.6

Thread 1 (Thread 0xf786b9c0 (LWP 5592)):
#0 0xf7fe270c in _dl_relocate_object () from /lib/ld-linux.so.2
#1 0xf7feac9d in dl_open_worker () from /lib/ld-linux.so.2
#2 0xf7ba271c in _dl_catch_exception () from /lib32/libc.so.6
#3 0xf7fea617 in _dl_open () from /lib/ld-linux.so.2
#4 0xf7f56ca4 in dlopen_doit () from /lib32/libdl.so.2
#5 0xf7ba271c in _dl_catch_exception () from /lib32/libc.so.6
#6 0xf7ba27c3 in _dl_catch_error () from /lib32/libc.so.6
#7 0xf7f575eb in _dlerror_run () from /lib32/libdl.so.2
#8 0xf7f56da6 in dlopen () from /lib32/libdl.so.2
#9 0xf7d2b80f in ?? ()
from /usr/local/games/Shadowrun Hong Kong Extended Edition/lib/libX11.so.6
#10 0xf7d2b93f in _XNoticeCreateBitmap ()
from /usr/local/games/Shadowrun Hong Kong Extended Edition/lib/libX11.so.6
#11 0xf7d2bf14 in XCreatePixmap ()
--Type <RET> for more, q to quit, c to continue without paging--
from /usr/local/games/Shadowrun Hong Kong Extended Edition/lib/libX11.so.6
#12 0xf7d2adf1 in XCreateBitmapFromData ()
from /usr/local/games/Shadowrun Hong Kong Extended Edition/lib/libX11.so.6
#13 0x088adc9b in ?? ()
#14 0x088ae261 in ?? ()
#15 0x088a8991 in ?? ()
#16 0x088aa7c7 in ?? ()
#17 0x0808e21c in ?? ()
#18 0xf7a6df39 in __libc_start_main () from /lib32/libc.so.6
#19 0x08090631 in ?? ()

Kind of hard to figure it out from this backtrace, but it looks like it's having trouble loading libXcursor.so.1 for some reason. If I cared, I'd look into it further, but it's neither your problem nor mine.

Edit: You may also want to check (via ldd) the libraries in SRHK_Data/Plugins/x86. I'm not sure SRHK even uses ScreenSelector.so, but it has a bunch of gtk & X libraries linked in.

Indeed, here there were many broken references, including the one to libsteam_api.so. There's something wront in the way that libraries paths are defined.

Actually, you can ignore the libsteam_api.so reference, as it will be properly resolved. The plugins use the plugin directory in their library path.

[SOLVED] I had messed up with libGL libraries, on Debian two OpenGL implementations are available: the more popular by MESA and a legacy release by NVIDIA. I had mixed them somehow, so I clean up and I assured that all packages refer to MESA implementation only.

(Can you mark this answer as a solution, please?)

It is not possible to mark your own post as an answer due to the reputation consequences (which I would think they could fix, but I guess they have their hands full ruining the storefront). Just leave it "unanswered."