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