The Windows installer for Groovy 2.5.8 is now available from Bintray: https://bintray.com/groovy/Distributions/download_file?file_path=groovy-2.5.8-installer.exe.

I've again included a preview of an msi built with WiX, which I'm seeking feedback on: https://bintray.com/groovy/Distributions/download_file?file_path=groovy-2.5.8+%28preview+installer%29.msi

Be aware that you need to fully uninstall the NSIS based Groovy installation before installing with an MSI installer.

-Keegan