The worse thing about games is that it's so hard to monetize the site with ads as none of the gamers want to click, they just want to play games and when you do get a click it ends up being for just 1 cent. Lucky you are getting just over 3 cents and not just 1 cents. Although saying that, I would have though some of them clicks were probably 4 - 6 cents each and some were also 1 - 2 cents each to make the average of just over 3 cents per click.
With a few MFA ads showing up on your site, 3.6 cents per click is not at all out of line and likely NOT from invalid clicks.