I don't know but for a contest worth 10 BTC, you should really set some rules properly. I couldn't find any rules and that's not a comfort for people wanting to participate. All it says is referrals must play 10 games but looking at the website, there's no one in chat and only 3 games available. Leaderboard is also not updated real time (I don't believe there is not even a single player referred).
And of course, proof of funds are needed. That's the bare minimum.
We have just run the website a few hours ago and haven't had any advertising campaigns at the moment besides this post. We will run advertising campaigns soon in the future and you will see more players.
We will transfer 11 bitcoin into this address (39CF9XzpiBHDjnRyadGJgebauNeCMUdaoi) to make proof. After that, we will withdraw it immediately because we won't keep bitcoins in hot wallet. We keep them in cold wallet.
OK cool that sounds really good. I'll check back in a few days to see if there are more players.
Also, I recommend you just store the BTC in a cold wallet. And then you only need to sign a message from the address to show that you own it, no need to show hot wallet.
Better still, use a respected forum escrow to hold the funds and start the thread. Then I GUARANTEE you will get people to play.