Criticizing G-d?

The realization came to me that there are many parts of Kohelet that seem to criticize G-d.

For example, in 8:14-17 the Neheneh brings up the idea of gamul, or theodicy, the question of why bad things happen to good people and vice versa. The Neheneh says that if G-d was merciful the bad would  go unpunished and the good would be rewarded, and if G-d was just, the bad person would be punished and the good person would be somewhat punished. The Neheneh declares that, because of this, there is no system in this world, that we live in a world of chaos and anarchy, seeming to suggest that G-d really isn't in control. He goes on to say that there will be no accounting for our actions in the next world, and once you're dead, that's it. Adios, muchacho. At the end of his final speech, the Amal is essentially an atheist. 

Then, in 10:11-14 the Chacham responds to the Yirei Elokim's belief in G-d's system of judgement: in this world there is a partnership between man and G-d and if we sin G-d gives us the opportunity to repent. In the next world, G-d is in complete control over us and will hold us accountable for our sins and punish us accordingly. The Chacham responds, saying that he is simply unable to the G-d's hand in this world and can't believe in the YE's system.

As you can see, much of Kohelet discusses G-d in a negative light. I find this to be very interesting for some reason. Perhaps it is because it's hard to see this book being included in the Tanach. Correct me if I'm wrong, but I'm not sure there is any other book in the Tanach that discusses or criticizes G-d in this manner. 

Now, this isn't necessarily a bad thing. I think Kohelet addresses some very real concerns that people still struggle with. I know that I myself have had some of the same doubts as the Neheneh and the Yirei Elokim. It can be incredibly difficult for me to see G-d's hand in this world sometimes. This is part of why the book of Kohelet is so fascinating to me. It holds nothing back. There is no censorship or subtlety. It gets straight to the point, exploring controversial and difficult subjects that, I think, are on our minds even to this day.