Here is the full list of all 16 Graveyard Shift achievements.
Score a 10000
Complete game in normal mode
Complete game in hard mode
Complete game in easy mode
Kill 500 ghosts
Throw 500 mushrooms
Kill 250 ghosts
Collect 1000 mushrooms
Score a 1000
Throw 100 mushrooms
Score a 100
Collect 500 mushrooms
Kill 100 ghosts
Kill three ghosts with one mushroom
Collect 250 mushrooms