Christopher Marlowe's Faustus mirrors itself as a study of ambition and despair. In the beginning of the story, Marlow presents his protagonist in all airs of sad self grandiosity. The story begins with Faustus expressing his huge ambitions, his vision of the present and future, and his plans to attempt a form of complete domination. Sadly, as the beginning Choir predicts, we already know that he is going to set himself for failure, but still the reader marvels at this man's hunger for power.
Meanwhile, as the story develops, we get to know the real Dr. Faustus. A petty and empty, hollow man with a dim wit, who is impulsive, and we could almost classify him as imprudent. Yet, considering the time when the character of Faustus was conceived, Marlow clearly wants to demonstrate the social characteristics of the Renaissance's break with the medieval mentality of a God that controls the fate of man: As a Renaissance man, Faustus demonstrates the feeling of want to control one's own fate.
With the contract that he makes with the Devil, he is basically uncovering his own weaknesses. He denies that hell exists even after he made the pact because we know he is in constant fear. He is tempted to repent, but continues to deny himself to do so. He is a staunch and stubborn character who got too much, and knew not what to do with it.
The only part when Faustus moves the reader to compassion is when, in his final hours, as he is about to be taken to eternal damnation, the best of him comes out, and he can see clearly where he stands. And it is then when his best words are expressed, and his more clear thinking is evident. As his end comes, despair sets in, yet, despair is a silent ghost that involves Faustus's entire existence, and his view of who he is and where he is going.
In many ways, Faustus' overriding sense of ambition leads to his despair. The idea of appropriating the world in accordance to one's own subjectivity creates an infinitely regressive cycle of subsuming vistas and horizons. This leads to despair as there is little in way of contentment, or the ability to simply "tarry for a moment." Faustus' pact with the devil that he would be able to represent the zenith of appropriation or control leads to despair for there is no sense of finality. Every moment of accomplishment is punctuated with the belief that there is more to appropriate. There can be little contentment or joy in this setting because of Faustus' own sense of ambition which knows no limits. In the end, his animating force of desire and ambition leads to despair.