Once you've installed all the Eclipse plugins, import the projects into Eclipse:
File -> Import... -> Gradle -> Gradle Project
Browse to the project root directory then click Build Model.
Eclipse may complain saying "SDK location not found." If that happens, create a file called local.properties:
sdk.dir = <path to Android SDK directory>
Once Build Model succeeds, select all the projects and click Finish.
Now you should be able to run the desktop version:
Right-click on the `dunwatch` folder -> Run As -> 2 Gradle Build...
In `Task execution order`, enter ":core:texturePacker, :desktop:run" then click Run