We have finally released a first release candidate for 0.7.
The changes compared to 0.6.2a are too numerous to list, main points would be:
* New graphics engine
* New GUI
* Kart and track animations
* New and improved tracks, karts, and items
* Shortcut/alternative way support for tracks
Compared to 0.7alpha3 challenges, unlocking etc. are now fully implemented.
Download from the sourceforge