Here is the full list of all 15 Iggys Zombie A-Pug-Alypse achievements.
Completed the Bedroom levels
Completed the Library levels
Completed the Kitchen levels
Completed the Graveyard levels
Complete the Lab levels
Complete the Museum levels
Completed the Garden levels
Collected all the stars in the Bedroom levels
Collected all the stars in the Library levels
Collected all the stars in the Kitchen levels
Collected all the stars in the Graveyard levels
Collected all the stars in the Lab levels
Collected all the stars in the Museum levels
Collected all the stars in the Garden levels
Collected all the stars