In order to play online, it is required that you create an account using a valid e-mail address. This e-mail address is used only to provide you with game notifications (which can be disabled in-app or via a link provided with each e-mail), and to provide a mechanism to reset your password.
I will not pass on your e-mail to any third party for any reason. Nor will I send you any unsolicited marketing e-mails. You will not be asked to disclose any other personal information at any point.
This game is a hobby project from a single developer who has no interest in monetising your personal information.
Offline play does not require any information from you at all.