The content is the same, don't worry! The prices might be different in different regions because the base price on itch.io is in USD and on Backerkit the base price is in CAD (Canadian dollars - I live in Canada and Kickstarter/Backerkit require me to use my own currency for the base price). Different sites use different currency conversion formulas, too, and the Euro may have lost value between then and now (North America is going through massive inflation issues). So the big difference is probably found in currency conversion formulas between USD/CAD/Euro. Please feel free to take advantage of whichever is the best deal for you, which it looks like you did!