I will admit that I play mainly on their mobile site, but I'm surprised to read all the previous comments because I've had nothing but good experiences at Rizk.
The mobile site runs great from my end and games all run very smoothly.
The only problem I've ever had here is my lack of luck and withdrawals, but that's not Rizk's fault. I'm sure it will come.
I joined up a long time ago but since then only made a few deposits now and then as I focused most of my business towards other casinos I was a VIP at. However, since recently closing my accounts at two of those regular sites (Trada and Guts) I have been looking for new sites to play at and Rizk has become one of those sites.
My only one issue with Rizk is the lack of rewards for regular high depositors who may burn through deposits and not get much play time in return.
As I said, through no fault of Rizk for some reason my luck has been terrible at their site, and after numerous fairly large deposits and short sessions over the past week, the only rewards I received in return for my loyalty was approximately $25 - $30 in free spins winnings from the Rizk Wheel.
The Rizk Wheel is an excellent concept and fun, however it seems it's not programmed to reward prizes according to a players expenditure, therefore to prizes are the same for someone who may have deposited $20, or a player that deposited a $1,000.
This does seem to mean the wheel is very fair and even, however it offers very little incentive for larger depositors to continue making larger deposits. Hence I started playing more regularly at another new site I tried Casinoroom as I was getting much better rewards for my larger deposits and better luck with the slots overall.
Despite the poor luck so far, I'll continue to play at Rizk because I like the fun site and Rizk wheel concept, however with very minimal loyalty rewards for larger depositors I think in the future I'll be giving Rizk the odd smaller deposit and leaving my larger deposits for some of the other sites I play at.
All in all an enjoyable experience despite the losses and no withdrawals ( yet

) so I recommend Rizk mainly for low rollers and give them a solid rating of 8/10.