Site is great, i liked site and it is responsive also with good contents, however here are some points:
slots-guide.eu is hosted on 188.65.114.122 IP which have other 923 domains hosted, many sites are porn sites on this IP, which does not seems good from Google point of view, instead take dedicated IP or any other shared IP
https://plus.google.com/102907255274133500492 – You can take branded company profile URL like https://plus.google.com/+slotsguide
Also this Twitter™ Account @slots_guide is free instead the one added on site (looks more branded as per your domain name)
Here are some 404 pages
http://slots-guide.eu/xmlrpc.php
Linked http://www.playtech.com/html/OnlineCatalogue/BrandedSlotsCatalogue/ from this page Time On Device – Slots Guide
I can share more points, but not sure if you will like my feedback