Here is the full list of all 22 Smash and Bash Monsters achievements.
Buy the Dagger
Kill the FIrst Boss
Start a game and received the Heirloom
Kill the Second Boss
Kill the Third Boss
Kill the Fourth Boss
Kill the Fith Boss
Kill the Sixth Boss
Kill the Seventh Boss
Kill the Eighth Boss
Have $1.000.000 or more
Kill 100.000 enemies in one match
Beat the game in less than 30 minutes
Beat the game in Ascension 0
Beat the game in Ascension 1
Beat the game in Ascension 2
Beat the game with all weapons bought
Beat the game without buying any weapons
Beat the game having bought all gadgets.
Beat the game without buying any gadget.
Set every option to be sold in the autosell tab
Sell a unique Item