In "A Deal with the Devil" by B.J. Sinz, readers are thrust into an enthralling narrative that masterfully intertwines themes of ambition, morality, and the consequences of one's choices. This novel, gripping from the start, offers more than just a thrilling plot; it delves deep into the psyche of its protagonist, Ethan Turner, a young, ambitious lawyer who finds himself caught in a Faustian bargain that promises power but demands a heavy price.

The book is structured around Ethan's meteoric rise in a prestigious law firm after he unknowingly makes a pact with a mysterious figure, who appears to be the epitome of success. Sinz excels in creating a palpable tension that keeps the readers on the edge of their seats, wondering just how far Ethan will go to achieve his dreams. The devilish contract offers him everything he believes he wants—status, money, and influence—but as the layers of the deal unfold, so does his realization of its true cost.

Sinz’s portrayal of Ethan is both complex and compelling. Throughout the novel, Ethan is depicted as a driven individual who initially sees the deal as a mere step towards his ultimate goal. However, as his ambitions begin to materialize, the ethical dilemmas and moral sacrifices involved begin to weigh heavily on him. The author does an excellent job of charting Ethan’s transformation from an ambitious idealist into a man haunted by his choices. This character evolution is one of the strengths of the book, offering a profound look at the internal conflicts that accompany such a sinister agreement.

The narrative is richly supported by a cast of well-developed secondary characters who either abet or counter Ethan's descent into the moral abyss. Among them is Claire, Ethan’s longtime girlfriend, who serves as both his moral compass and his grounding force. Claire's character is instrumental in highlighting the stark contrasts between the life Ethan might have led and the one he is propelling himself towards. Her evolution throughout the story adds depth to the narrative, stressing the personal losses that come with Ethan’s choices.

In terms of thematic exploration, Sinz doesn’t shy away from the heavy. The story is a modern-day allegory about the dangers of unbridled ambition and the seductive nature of power. Through Ethan’s story, Sinz explores how the pursuit of power can lead to a disconnect from one’s values and ultimately, one’s happiness. The moral quandaries presented in the book pose significant questions about the nature of success and the ethical lines we are willing to cross to achieve it.

Stylistically, Sinz’s writing is sharp and evocative, capable of constructing vivid scenes that pull the reader directly into the heart of the action. The dialogue is crafted with a natural ear for rhythm and character voice, which provides authenticity to the interactions. Particularly notable is the depiction of the legal environments and courtroom dramas, which showcase Sinz's grasp of legal procedures, adding a layer of realism to the tale.

However, the novel is not without its shortcomings. At times, the plot relies heavily on coincidences that might stretch the reader's willingness to suspend disbelief. Furthermore, the pacing, while generally well-handled, does suffer in parts where the introspective musings of the protagonist might slow down the narrative drive. Despite these minor issues, the overarching storyline remains enthralling and thought-provoking, ensuring that readers stay engaged and contemplative long after they turn the final page.

The climax of the book is both dramatic and fitting, with a confrontation that tests Ethan's resolve and forces him to confront the true nature of his pact. It is in these final chapters that Sinz demonstrates a powerful command over plot resolution and thematic closure, leaving the reader satisfied yet reflective on the broader moral lessons imparted.

In conclusion, "A Deal with the Devil" by B.J. Sinz is a compelling read, rich with moral complexities and anchored by a gripping storyline. While it navigates the well-trodden paths of Faustian tales, it does so with a fresh perspective that resonates with contemporary societal issues. The novel is a profound reminder of the old adage that power corrupts, and a cautionary tale that the price of one's soul is the steepest transaction of all. This book is highly recommended for those who enjoy thrillers with depth, and narratives that challenge both the characters and their readers morally and ethically.