if anyone played the demo and then bought the game you can keep the demo save using the following js code (you need to first use a breakpoint in their js code)
save = FS.readFile("/user_data/cdata/werxzy_infinimoes_demo.p8d.txt")
var string = new TextDecoder().decode(save);
then copy the string content to the save game at
%appdata%\Roaming\pico-8\cdata
or wherever it is in linux/mac