You can install from the zip by pointing your Eclipse update manager to the downloaded zip file and following the installation instructions provided by the update manager.
Groovy-Eclipse 2.1.1.RC1 includes Groovy 1.7.5 and is installable on Eclipse 3.6.0 and 3.6.1. There are no plans to release a 3.5 version of this release.
Over 60 65 issues have been addressed for this release.
The Groovy-Eclipse team would like to thank Nieraj Singh for his excellent work on the new Groovy-Eclipse Quick Fix feature. We'd also like to thank the community for continuing to provide feedback, raising issues, and for telling us what you need. Keep it up! You are what keeps this project alive.
The 2.1.1 final release is scheduled for a week from now to coincide with the 2.5.2 release of the SpringSource Tool Suite. Because this version is a release candidate, only critical bug fixes will be made between now and the final release.