Hi Phillipp,
Please try this:
<h2>Review [cred-post-parent get='title']</h2> <a href="[cred-post-parent get='url']">Back to [cred-post-parent get='title']</a>
More help:
Bonus – Display Information of Parent Pages
http://wp-types.com/documentation/user-guides/cred-forms-for-child-content/