Here is the full list of all 8 Curvatron achievements.
Get 4000 points in Evergrowing mode
Finish every Hardcore level
Finish every level in the Adventure mode
Have two players kiss in Multiplayer mode
Finish a community level
Get 30 points in Classic mode, collecting all shrink powerups
Get 30 points in Classic mode without collecting any shrink powerups
Take a bite out of yourself