Dev_Null: In case it's relevant; I just discovered the dependency list on the store page:
$apt-show-versions libc6:i386 libasound2:i386 libasound2-data:i386 libasound2-plugins:i386 libstdc++6:i386 libx11-6:i386 libxau6:i386 libxcb1:i386 libxcursor1:i386 libxdmcp6:i386 libxext6:i386 libxfixes3:i386 libxinerama1:i386 libxrandr2:i386 libxrender1:i386 libglu1:i386
libasound2-data not available for architecture i386
libasound2-plugins:i386/trusty 1.0.27-2ubuntu2 uptodate
libasound2:i386/trusty 1.0.27.2-3ubuntu7 uptodate
libc6:i386/trusty-security 2.19-0ubuntu6.7 uptodate
libglu1 not available for architecture i386
libstdc++6:i386/trusty-security 4.8.4-2ubuntu1~14.04.3 uptodate
libx11-6:i386/trusty 2:1.6.2-1ubuntu2 uptodate
libxau6:i386/trusty 1:1.0.8-1 uptodate
libxcb1:i386/trusty 1.10-2ubuntu1 uptodate
libxcursor1:i386/trusty 1:1.1.14-1 uptodate
libxdmcp6:i386/trusty 1:1.1.1-1 uptodate
libxext6:i386/trusty-security 2:1.3.2-1ubuntu0.0.14.04.1 uptodate
libxfixes3:i386/trusty-security 1:5.0.1-1ubuntu1.1 uptodate
libxinerama1:i386/trusty 2:1.1.3-1 uptodate
libxrandr2:i386/trusty 2:1.4.2-1 uptodate
libxrender1:i386/trusty-security 1:0.9.8-1build0.14.04.1 uptodate
$ apt-show-versions libasound2-data libglu1
libasound2-data:all/trusty 1.0.27.2-3ubuntu7 uptodate
libglu1 not installed
$ sudo apt-get install libglu1
...
Note, selecting 'libglu1-mesa' instead of 'libglu1'
libglu1-mesa is already the newest version.
$ apt-show-versions libglu1-mesa
libglu1-mesa:amd64/trusty 9.0.0-2 uptodate
libglu1-mesa:i386/trusty 9.0.0-2 uptodate
So as long as you accept libglu1-mesa for libglu1, it looks like I'm up-to-date.
BTW - the 64 bit build seems to be correctly showing the launcher. It wasn't up on GoG because of an issue in our release process this morning, but we are working on getting that one up as soon as possible. That might be all you need, or at least help!