You don't have to wait for a formal release to try new features in Gilgamesh. You can build your own copy from the source. (And while you are at it, also play around in the internals and see if you can make the game your own.)
Gilgamesh is distributed inside of the Clay framework repository as an example. The installer for clay knows how to knit in all of the packages that the framework and gilgamesh are going to need to run. You just need the fossil scm program installed somewhere in your path, or in a convenient place to hard cast it.
fossil clone http://fossil.etoyoc.com/fossil/clay ~/Downloads/clay.fossil mkdir -p ~/build/clay cd ~/build/clay fossil open ~/Downloads/clay.fossil tclsh make.tcl install ~/games/gilgamesh
These instructions will download the clay sources, unpack them in ~/build/clay, and then use those sources to build an image of the Gilgamesh software installed in ~/games/gilgamesh. Feel free to adjust the paths to taste.
Once unpacked, you can run the game from wherever you installed it:
tclsh8.6 ~/games/gilgamesh/main.tcl
If you want to update the software at a future point:
cd ~/build/clay fossil update tclsh make.tcl install ~/games/gilgamesh
These instructions will either produce a new image, or replace an already installed image of the game. Note that you can place the install path anywhere you deem fit, and multiple copies of gilgamesh will happily live side by side with one another, even if they are using radically different version of the underlying libraries. This is because in addition to the gilgamesh software proper, the installer also provides a snapshot of all of the external modules that Gilgamesh relies on.