Here is the full list of all 12 Mad Tracks achievements worth 200 gamerscore. It takes around 3-4 hours to unlock all of the achievements on Xbox 360.
You gathered all 15 gold medals. You're great. Think you can do better?
You did not pick up any power ups for 3 laps in ‘Black out’. Good job! Now you can brag about it!
You gathered at least 12 silver or gold medals. You're very good, try a little harder now.
You gathered 11 medals. You're good... with room for improvement!
You unlocked all the power ups! Now try those challenges again!
You finished 5 different challenges with friends on split screen.
You won a pool game without pocketing the black ball. Admit this achievement was easy!
Pick up 5 golden flags in 'Black out' and finish the race.
Finish ‘Toy race’ 20 times in a row.
Find 5 golden aliens in 'Toy race' and finish the race.
Come in 1st place against 5 hard A.I., 5 times in a row in 'Speed racer'!
Beat 1 minute 15 seconds on 'Fast food'.