Finally, the demo of Calvin is available to download. :)
I hope you'll enjoy it. Please comment or send me a message if you have any feedback. Thank you very much!
Pour les francophones : Demo v0.2 (version française intégrale) (WINDOWS)
For english speakers : Demo v0.2 (french voices with english subtitles) (WINDOWS)
EDIT: You can download it on itch.io too : Calvin on itch.io