Dear Thomas,
We have just released CRED 1.2.5 which is a bugfix release. Our next target is to replace the zebra form library completely:
http://wp-types.com/2014/02/cred-1-2-5-bugs-crushed/
Meanwhile, you can manually add javascript validation like this user here:
http://wp-types.com/forums/topic/cred-how-to-make-fields-required/
Please let me know if you are satisfied with my answer and if I can help you with any other questions you might have.
Regards,
Caridad