Here is the full list of all 60 Monster Bash HD achievements.
Save 4 pets with 1 one shot
Kill 50 Witches
Kill 25 Pumpkin Heads
Complete all episodes
Complete Episode 3
Defeat Nemessis in all 3 episodes.
Get 100 Check points
Kill 50 Spiders
Kill 50 eyeballs
Kill Igor without killing any of his flies
Complete Episode 2
Finish any episode on Hard difficulty
Kill 50 enemies with the Rocket
Get petrified 5 times
Beat Cyclope without getting thrown in the air
Read every page of the instructions book in the menu
Finish an entire level without taking any damage
Shoot 10000 rocks from slingshot
Collect 250 peppermints
Get all bonuses on any level
Kill 100 Zombies
Collect 1000 candies
Collect 500 Candy Kisses
Kill 50 Thing Hands
Complete Episode 1
Beat par time on any level.
Kill enemy with pushable object
Die 50 Times
Save 100 pets
Destroy 50 treasure chests
Get 5 heart pickups while having full health.
Break 100 objects
Smash 10 zombie heads before they hit the ground.
Water a plant
Get 8x splatter bonus on Skull Watcher.
Crawl over 100 tiles
Score splatter bonus on 50 skulls
...
Finish E1L06 without getting hurt
Finish any non-boss level in 1 minute or less
Collect all the Johnnies in the game
Destroy all Skull Watchers in the game
Break all treasure chests in the game
Beat all par times in the game
Collect all bonus pickups in the game
Complete E1L02 without disturbing the hanged skeletons
Solve a puzzle requiring the use of blocks
Extinguish the candle with fireball
Ride 50 brooms
Create and post user level
Beat Count Chuck...fast
Race Frank Lloyd Rat to the other side of E1L01 and win.
Finish any episode on Nightmare difficulty
Finish the entire game with 100% on every level
Find all the secrets
Complete all achievements