Full list of all 14 Cro-Mag Rally achievements worth 200 gamerscore. It takes around 3-4 hours to unlock all of the achievements on Windows Phone.
Finish a race in First Place
Finish a race in First, Second, or Third Place on Hard difficulty
Finish in First Place on all tracks
In a Gather game, collect all the tokens and come in First, Second, or Third
Collect all the tokens from all the tracks in Gather races
Complete a race with each vehicle type
Stay airborne for more than 2 seconds
Inflict damage on every opponent in a single race
Win a race without using any power-ups
Complete 6 races as Brog
Complete 6 races as Grag
Collect 100 tokens in Gather races
Finish Glacier in 5 minutes or less
Make the Desert track less... green