I would like advice about my failure game

Almost 1 year ago I've released my first own game. I wanted to build a casual game, easy to use, with nice soundtrack and very hard to play! My idea was to give a simple killtime game. In metro, in a waiting room etc.

I seriously undertook in this project with two of my friends (for graphics stuff), and we have made this Pixel-Art game: it's name is "Rolly Monkey" and you can find it in the Google Play.

One year passed, but it looks like that no one will even find the game... I don't think that it's a bad game. It's technically good, without bugs or glitches, we have also tried Facebook and Ig ads, with just few results.

After the first two/three weeks, where the game seemed to be going well, installs has stopped and very few peoples now plays it.
I still believe that it's a nice game (I usually play it), but I must admit that, until now, it was a failure. So, I would like ad advice: is just my idea bad or I've wrong something during promotion? I feel that I was not able to touch the target people to where the game was destinated

I ask for your help, just to understand and improve in my next projects.

Thank you!

Well, I've done classic "family and friends" to get some good reviews (You can still see it, there are almost 100), share on facebook relevant groups (self promotions, indie games and so on..), and at least paid promotion on Facebook and Instagram (with video) for about 50$..