I played some games some weeks ago and after some playing I removed them. But when I reinstall them again I see that they keep my data. How is it possible? I think it's related to my iCloud acount and store data there but I don't want to continue that game. I want to start again from zero. What can I do?
Apps can persist data on iOS across uninstall/reinstall of apps in the keychain, iCloud or third party cloud services (like Dropbox). You have control over iCloud data, however there is no easy way of clearing the keychain entries created by the app.