tl;dr Are US Citizens not (legally) allowed to play or is there just restrictions on US IPs? I'm a little confused on the legality.
As I said above:
The only thing restricted to IP addresses in certain locations is requesting a deposit address. The rest of the site including withdrawals works from anywhere in the world.
I'm not a lawyer but I believe that Crypto-Games will have taken legal advice that has led them to only restrict deposits.