The Steam version is paid mostly as a way for people to support Pixelorama's development. The itch.io and Steam versions don't have any differences, apart from the fact that Steam users benefit from certain features that come from Steam itself, such as auto-updates and achievements, and perhaps cloud storage in the future. You can read this FAQ for more information: https://orama-interactive.itch.io/pixelorama/devlog/720195/pixelorama-is-coming-...