OK, believe it or not I completed this by winning 17eur with the 20 spins and then playing through that 40x (717ish euros). I tried to cash out 40 euros.
You can't convert it to bitcoins on the site. Most of the cash out options are grey and the live support said that the free spin bonus wasn't available for bitcoin.
In my opinion they shouldn't even advertise here if you can't withdraw bitcoins. I think it' s a scam. I mean, I'm still going to get the EUR out but what a pain in the ass. Samatha also claims I should have read some rules that explained this to me but I don't see it here:
http://imgur.com/a/HJPlD