open File Explorer and
paste the following C:\Program Files (x86)\Steam\userdata\<your_id> \1066780\local\settings.lua

then open the settings.lua in notepad

and press ctrl + f
and put experimentalMapSizes in the Find what box
then change false to true
then save and close notepad and then fire up the game
then create a new free game and a the new world sizes are
tiny,huge and Megalomaniac

open File Explorer and
paste the following ~/. local/share/Steam/userdata/<your_id> /1066780/local/settings.lua

then open the settings.lua in a text editor of your choice

and press ctrl + f
then change false to true
then save and close the text editor of your choice and then fire up the game
then create a new free game and a the new world sizes are
tiny,huge and Megalomaniac

open File Explorer and
paste the following ~/Library/Application Support/Steam/userdata/<your_id> /1066780/local/settings.lua

then open the settings.lua in TextEdit
and press ⌘ command + f
then change false to true
then save and close TextEdit and then fire up the game
then create a new free game and a the new world sizes are
tiny,huge and Megalomaniac