All of gambling games required luck and no exceptions about that but since this is new site people still looking around to find the feedback but smart contract address showing there is no players since several days ago because there is no upcoming transactions since that and probably because the concept of the game is too simple people not too interested to play
There are very few players because we haven't advertised the game yet 
We are thinking about marketing. By the way, can you suggest the right way?
it depends on your budget, really
the right way would be investing in marketing when your product is ready and you are confident it will sell
i.e. you spend 1000$ on promotion and you get 1000$++ worth of customers to your site - in your case gamblers who deposit money and play
the easiest way would be buying targeted ads with one of the bitcoin ad sites, it won't cost you an arm and leg
and will send you an initial wave of people to see how is your site doing retentionwise
start with mellowads or anonymous ads, for example, buy 0.03 bitcoin worth of ads and check the google stats
alternatively, you can post on bitcoin and gambling forums, similar topic as you have here
this will be free but very time consuming, but a forum post like this is a very effective anchor link that will be bringing people to your site for quite some time
there are many ways to market, think about a promotion for the forum users, to try the game for free, a promotion code, a contest etc.
be creative
