It looks like Critque is a branch of Gerrit. The user interface is similar. I assume that Critque is Grerrit with a bunch of Google-specific changes.

Gerrit itself is an interesting review tool. It uses Git references to manage the review changeset before it is merged into the parent branch.

I used it on a project that used Redmine for issue tracking and Gerrit for the git repo and review tool. It took a bit to get used to how to git to push changes to a Gerrit review so we ended up using Git extensions to manage that.