The plugin seems to work as advertised. Nice work.
This is a relatively small problem, but it would be nice if I could get an answer: if I enter an invalid reCAPTCHA, the Validation Errors response from Contact Form 7 is shown, rather than a message saying it's an invalid reCAPTCHA.
I've modified the error response in Contact Form 7 so that it hints that the problem might be caused an incorrect reCAPTCHA, but it would be nice if the error message was specific to the reCAPTCHA problem.
So here's my question: Will this error be generated for any reason other than an invalid reCAPTCHA entry?
If not, then it's easy enough to make the error response say to try the reCAPTCHA again. Otherwise, it would be nice if a specific error were provided for reCAPTCHA.