Hello.
I've installed all necessary 32 bit libraries - sudo apt-get install libc6:i386 libasound2:i386 libasound2-data:i386 libasound2-plugins:i386 libgtk2.0-0:i386 libsdl2-2.0-0:i386 libsdl2-image-2.0-0:i386 libfreetype6:i386 libcurl3:i386- but i'm still missing one lib, mentioned in thread title.
Here is ldd output:
ldd witcher2 | grep not
libopenal-eon.so.1 => not found
Maybe anyone with working Linux Witcher 2 installation could locate this library, if it exists in his system and could tell me which package contain it or share this lib by any public file storage, please? Any other help and suggestions are welcome too =)

I think this library comes with the game and should be in the game folder (can't check it right now because of the huge download). I don't think it's part of an external package as it's probably the eON wrapped version of the OpenAL library.
Maybe it's a path issue. You could also try creating a symbolic link in /usr/lib32/

I got the same problem with OP.

I purchased witcher2 four days ago and I am facing the exact same problem
It seems that it's impossible to locate the libopenal-eon.so.1 as there are no packages providing it for my distro as well.
A thorough check through google was unable to provide me with any hints about this library apart from this post and the fact that people usually from steam having this library on their system no matter the distro.

Therefore I tend to believe that it is a library that should be provided with the game but for a reason unknown exec fail to locate

Ok
it was a corrupted tar.gz and several files were missing.

Unfortunately 20 GB file to download makes the checking rather tedious.

Anyway it's working splendidly in openSUSE 13.2

I like that username and avatar. Can you all do us a favour, and stroll out of your office, with bat in hand, and march into CDPR's offices and convince them to release The Witcher 3 for Linux? :)