Here is the full list of all 24 Secrets of Magic 2: Witches and Wizards achievements.
Upgrade twice the Hammer power-up
Explode at least 30 bombs - bonus power-up
Upgrade any power-up for the first time
Make a combo of 25x or higher
Make a combo of 20x
Make a combo of 15x
Finish the first 10 levels with 3 stars in each level
Play 20 levels in a row
Get 200 stars
Destroy at least 650 wooden gates
Destroy at least 120 imps
Destroy at least 380 stones
Play 50 levels
Destroy at least 280 spider webs
Destroy at least 28 spiders
Destroy at least 50 big rocks
Collect at least 78 crystals of any kind
Upgrade twice the Wand power-up
Upgrade twice the Torch power-up
Upgrade twice the Stake power-up
Upgrade twice the Whirlwind power-up
Upgrade twice the Lightning power-up
Finish all the levels in Challenge mode
Get 300 stars