Originally Posted by vivanguarda
Are there debug commands to know what's important to install instead of complete Gnome?
Unless it isn't in README or some other documentation, ldd could help. If you have binary (eg. from ubuntu package) ldd will print it's shared libraries dependencies.
$ ldd /path/to/binary
Compare this listing with available libraries (Slackware core, SlackBuilds or grab sources), get all dependencies and try rebuild it on Slackware.