Here is the full list of all 16 Wizard Slime achievements.
Newbie
Beat the "Trippie" level
Beat the "Booming" level
Beat the "Party" level
Beat the "Corner" level
Beat the "Monster" level
Beat the "Afterparty" level
Beat the "Cornered" level
Beat the "Hallway" level
Beat the "Ambush" level
Beat the "Lobby" level
Beat the "Home" level
Beat the "Path" level
Beat the "Gate" level
Beat the "Hall" level
Beat the "Arena" level