I also have this problem, looks like the game is linked against an old version of OpenSSL.

I'm on Fedora 29 and I've tried symlinking
~/GOG Games/Icewind Dale Enhanced Edition/game/libssl.so.1.0.0 to /usr/lib64/libssl.so.1.0.2o
and also symlinking
~/GOG Games/Icewind Dale Enhanced Edition/libcrypto.so.1.0.0 to /usr/lib64/libcrypto.so.1.0.2o

e.g.
[jrose@ryzen2700x-allyour-net game]$ ls -la
total 24292
drwx------. 8 jrose jrose 4096 Feb 21 20:42 .
drwx------. 6 jrose jrose 4096 Feb 21 20:37 ..
-rwxr-xr-x. 1 jrose jrose 527426 Feb 21 20:34 chitin.key
drwx------. 2 jrose jrose 4096 Feb 21 20:34 data
-rwxr-xr-x. 1 jrose jrose 100 Feb 21 20:34 engine.lua
-rwxr-xr-x. 1 jrose jrose 12014204 Feb 21 20:34 IcewindDale
-rwxr-xr-x. 1 jrose jrose 12283792 Feb 21 20:34 IcewindDale64
drwx------. 12 jrose jrose 4096 Feb 21 20:34 lang
lrwxrwxrwx. 1 jrose jrose 30 Feb 21 20:42 libcrypto.so.1.0.0 -> /usr/lib64/libcrypto.so.1.0.2o
lrwxrwxrwx. 1 jrose jrose 27 Feb 21 20:42 libssl.so.1.0.0 -> /usr/lib64/libssl.so.1.0.2o
drwx------. 2 jrose jrose 4096 Feb 21 20:34 movies
drwx------. 119 jrose jrose 12288 Feb 21 20:34 music
drwx------. 2 jrose jrose 4096 Feb 21 20:34 override
drwx------. 2 jrose jrose 4096 Feb 21 20:34 scripts

but then it complains as follows:

Running Icewind Dale: Enhanced Edition
./IcewindDale64: libcrypto.so.1.0.0: version `OPENSSL_1.0.0' not found (required by ./IcewindDale64)
./IcewindDale64: libssl.so.1.0.0: version `OPENSSL_1.0.0' not found (required by ./IcewindDale64)

I'm no shared library master either but i think the game is loading the files and then not finding the correct version symbols in said files and crashing out.

I think the developer(s) may need to fix?

deleted

I have the same issue on Debian 10.

Any help from GOG?

OK, this seems to work on Debian 10 (game started, I got into menu and it haven't crashed so far):

1 .Download libssl1.0.0 manually from Debian Jessie archive

packages.debian.org/jessie/libssl1.0.0 (click the architecture -- probably amd64 -- link below)

2. Use Open terminal, go wherever you've downloaded it and extract it

cd Downloads
ar x libssl1.0.0_*.deb
tar -xf data.tar.gz

you can delete the rest of the files and the .deb

rm data.tar.gx control.tar.gz libssl1.0.0_*.deb

3. Move the extracted directory to your game's directory

mv usr ~/"GOG Games/Icewind Dale Enhanced Edition"


4. Start the game from terminal like this

cd ~/"GOG Games/Icewind Dale Enhanced Edition"
LD_PRELOAD=usr/lib/x86_64-linux-gnu/libssl.so.1.0.0 ./start.sh

5. Bonus - You can edit start.sh and add this line near the top of the file (AFTER first line)

export LD_PRELOAD="$HOME/GOG Games/Icewind Dale Enhanced Edition/usr/lib/x86_64-linux-gnu/libssl.so.1.0.0"

After this step the game should start normally from your desktop menu.

AloisMahdal gave a good solution above. Here is a solution I used in Debian that is similar; it allows you to install the needed files from the jessie repository, using your package manager. This puts the files in the right location so that they can be used by anything in your system.

Add this line to your "/etc/apt/sources.list" file (it will require root permission):

deb http://security.debian.org/debian-security jessie/updates main

Or, you can open Synaptic and add a new repository, with:

URI: http://security.debian.org/debian-security
Distribution: jessie/updates
Section(s): main

Then, using Synaptic, search for the libssl1.0.0 package and install it.

This solution came from this site:
https://packages.debian.org/jessie/amd64/libssl1.0.0/download

If anyone else is looking for a solution to this problem, and you have Steam installed, you can do a local file search in your home directory for libssl.so.1.0.0 and just copy that file from the x66_64-linux-gnu folder to /usr/lib/x86_64-linux-gnu. You will need to do the same for libcrypto.so.1.0.0

The commands on my system looked like this:

cd ~/.steam/debian-installation/ubuntu12_32/steam-runtime/lib/x86_64-linux-gnu

sudo cp libssl.so.1.0.0 /usr/lib/x86_64-linux-gnu

sudo cp libcrypto.so.1.0.0 /usr/lib/x86_64-linux-gnu

Probably better to do it that way, vs. a symlink, on the off chance that Steam moves stuff around. You might also want to compress those files and save them somewhere on the off chance that you need them sometime and you have said goodbye to Steam. It's a little insane that the enhanced edition requires a library from Debian Jessie.

But I've always said, old Windows versions of games run better on Linux through wine, than old native Linux versions of games do. So if all else fails, it probably wouldn't be that difficult to get the Windows version running on wine.

gawd this perpetually thrown around here stuff *is* dumb

but hey it's the layman's opinion aka the majority's. still bugs me out tho...