I recently published my first Android game (https://play.google.com/store/apps/details?id=com.foogacy.chainy.free) and no one is downloading it. I really mean no one. 0 downloads excluding a couple of friends of mine.

The game is very simple with an even simpler graphic (I am not really good at it!) but I do not think that's the issue as there are worst things out there.

What can I do to advertise it for free? I do not want to spam here and there.

Many thanks!