You can buy themes for your player dungeon for 150 MOS or 1.5 million coins. Once a particular theme is bought you can change to it without further purchase, this includes the default Cave theme that is automatically available. To change to or buy a theme, be in your dungeon and select Island from the Build Menu.
Image collection of some themes used with Rapota's dungeon: https://imgur.com/a/mVUS31d
Cave - default[]
Snow[]
Ancient[]
Ice[]
Cathedral[]
Sand[]
Jail[]
Hell[]
Pernau[]
Clouds[]
Mushroom Cave[]
