After hitting play on the Launcher, a crash window comes up. No initial screens or anything.

h t t p s : / / pastebin.com / 4BQVu9aZ (remove spaces due to GOG forum idiocy)

In the directory I copied "FreeType" to "freetype", then re-ran it to test and the following error
still causes it to crash... so there are deeper issues here.

h t t p s : / / pastebin.com / wvmk3c8m (remove spaces due to GOG forum idiocy)

At least I'm not alone on this one. I'm on Mojave.

Instead of copying the FreeType, I did a hardlink:

cd "Place where GOG install your games"
pushd RebelGalaxy.app/Contents/Frameworks/FreeType.framework/Versions/Current
ln FreeType freetype
popd
RebelGalaxy.app/Contents/MacOS/RebelGalaxyGoG

and then I got the following error message:

[i]
SceneManagerFactory for type 'DefaultSceneManager' registered.
Registering ResourceManager for type Material
Registering ResourceManager for type Mesh
Registering ResourceManager for type Skeleton
MovableObjectFactory for type 'ParticleSystem' registered.
ArchiveFactory for archive type FileSystem registered.
DDS codec registering
FreeImage version: 3.16.0
This program uses FreeImage, a free, open source image library supporting all common bitmap formats. See http://freeimage.sourceforge.net for details
Supported formats: bmp,ico,jpg,jif,jpeg,jpe,jng,koa,iff,lbm,mng,pbm,pbm,pcd,pcx,pgm,pgm,png,ppm,ppm,ras,tga,targa,tif,tiff,wap,wb mp,wbm,psd,cut,xbm,xpm,gif,hdr,g3,sgi,rgb,rgba,bw,exr,j2k,j2c,jp2,pfm,pct,pict,pic,3fr,arw,bay,bmq,cap,cine,cr 2,crw,cs1,dc2,dcr,drf,dsc,dng,erf,fff,ia,iiq,k25,kc2,kdc,mdc,mef,mos,mrw,nef,nrw,orf,pef,ptx,pxn,qtk,raf,raw,r dc,rw2,rwl,rwz,sr2,srf,srw,sti,webp
Registering ResourceManager for type HighLevelGpuProgram
Registering ResourceManager for type Compositor
MovableObjectFactory for type 'Entity' registered.
MovableObjectFactory for type 'Light' registered.
MovableObjectFactory for type 'BillboardSet' registered.
MovableObjectFactory for type 'ManualObject' registered.
MovableObjectFactory for type 'BillboardChain' registered.
MovableObjectFactory for type 'RibbonTrail' registered.
*-*-* OGRE Initialising
*-*-* Version 2.1.0- Stable - (Double Damage)
Installing plugin: GL RenderSystem
OpenGL Rendering Subsystem created.
Plugin successfully installed
Installing plugin: Octree Scene Manager
Plugin successfully installed
Installing plugin: Bink Video Plugin
Plugin successfully installed
Setting YRatio Init - 0.75
Signing in...
Assertion failed: (false), function openResource, file /Users/travisbaldree/Documents/spacegame/trunk/externals/ogre_1_9/OgreMain/src/OgreResourceGroupManager.cpp, line 267.
Abort trap: 6
[/i]

What means the problem is OGRE now. (sigh)

The Trap 6 thingy is related to a file not found, what means the file is missing, or the code is looking for it with the wrong case - damned Windows programmers that dont tell a uppercase letter from the lower.

I'm working on it and I will advise any changes.