Sharkoin.com is a new gaming site (abut 2 months old) that offers one game. I was lucky and had won $1600. on the site. All the problems began when I went to withdraw and the operator began using numerous excuses as to why he wasn't going to pay me. First he said because I had more than one account, one on my phone and one on my desktop. Then it was because he said I was using bots or robots to manipulate his site into letting me win, I explained I had no idea how to get a bot much less use one so that excuse was not valid either. The funny thing was I called him out in the end by asking if all of these rules were the reason I wasn't getting paid then why wouldn't they be listed on his website, he said they were but then I provided him screenshots of his website (using googles last update cached pages) proving that he was adding these rules just prior to emailing me and telling me that since I broke the rules I wasn't getting paid. He stopped responding at this point and my opinion he is a total fraud.
He may pay smaller wins just to keep the scam going, but don't expect any kind of larger withdraw. I guess when he was setting up his gaming site for bitcoins that on occasion player do win and they want to withdraw without any problems, perhaps he was hoping nobody would win until much later when he had accumulated a few bitcoin.