The plugin works great for the default admin, but it doesn't work for any other users.
I get "Google Authenticator Settings" when editing any user other than the default admin.
Under "Google Authenticator Settings" I get two check boxes:
"Hide settings from user"
Unlike the default admin, there is no QR code or codes or anything for other users. Just the two check boxes. Clicking "active" leaves the user unable to login (as there is no way to get them a google code?) while unchecking "active" will allow them to login--without any google auth.