Here is the full list of all 13 Panic Porcupine achievements worth 1,000 gamerscore.
Go around a loop
Complete the first level
Reach top speed
Earn an egg medal
Die 500 times
Complete the game 100%
Complete the first world
Defeat the final boss
Collect 1000 eggs
Get past the beginning of "cirque du ricochet" without touching any of the bumpers
Beat "Sizzler" without landing on bone platform.
Launch over saws in buzzsaw blast.
Beat Saw Speedway in under 20 seconds.