According to this post:
http://www.gog.com/forum/general/the_what_did_just_update_thread/post2016
The new V2.0 of messiah doesn't just update the installer it also includes the GLIDE executable and nGLIDE, setting GLIDE mode to default
Can anyone who's had issues try again with the new V2.0 version and report back?
Thanks

I've downloaded the latest version from gog and the default 3dfx exe works fine, however it's forced to low resolution textures so it probably doesn't look as good as it could.

The D3D version doesn't allow to change the resolution and is stuck at 640*480, even with the command line params people mention.

I do not understand why GoG does not solve the problem!