- Bizarro Episode: The sixth and final book deviates heavily from the rest of the series, being mostly told from a first-person perspective, and featuring aliens, time travel, and alternate universes.
- Darkness-Induced Audience Apathy: In the fourth book, Sparta and Blake are separated, and Sparta all but burns her bridges with the Space Board, then gets hooked on drugs, murders a bunch of people, attempts to sabotage a Space Board mission, and ultimately suffers a nervous breakdown. Paul Preuss himself conceded that he feared many readers would abandon the series after reading it.
- Fanservice: The series has nude scenes and sex scenes throughout, but the fifth book really takes the cake; Towards the end, Sparta abandons her clothes and spends the rest of the book swimming nude around the world-ship.
- Les Yay: The second book opens with Sparta receiving a massage from another woman.
- Moral Event Horizon: Ari Nagy, Sparta's mother, willingly handed her own daughter over to the Free Spirit cult, and unlike her husband Jozsef, she's not sorry. On top of that, she let her daughter believe that the Free Spirit had killed her and Jozsef, resulting in Sparta nearly throwing her life away on a poorly-planned vendetta.
- Nightmare Fuel: The super-extendable needles from the first book can be this if you're Afraid of Needles.
- Paranoia Fuel: Salamander can give people false memories...
- Strangled by the Red String: Sparta and Blake's relationship is more told than shown, and relies heavily upon the notion that constantly rescuing someone inevitably results in them falling in love with you.
- Tear Jerker: Kara Antreen's fate at the end of the first book; She ends up with her memories thoroughly wiped by Sparta.
- They Wasted a Perfectly Good Character:
- The first three books invest a great deal of time building up the Free Spirit into a major threat... and then Sparta kills off their leaders and the Orange Man halfway through the fourth book.
- In the second book, Blake infiltrates the Free Spirit, and meets several of its newest recruits and learns of their backgrounds. Only one of those new recruits appears later.
- They Wasted a Perfectly Good Plot:
- Sparta and Blake's hunt for the Free Spirit ends abruptly in the fourth book, and then the series morphs into a Cosmic Horror Story. Most fans seem to agree that the Free Spirit plot was much more interesting.
- Each book explores a different planet, its unique colonization challenges, and the political situations that emerge from importing humans there (like Mars' communism, or Ganymede's hotbeds of separatism, or Venus' extreme capitalism.) None of these subplots are ever followed up in subsequent books.
- True Art Is Angsty: The fourth book features Sparta breaking her ties with the Space Board, getting hooked on drugs, killing a bunch of people, attempting to sabotage a Space Board operation, and suffering a nervous breakdown and temporarily losing her enhanced vision. Preuss has justified all this, saying that character development requires confronting despair and figuring out a way past it.
YMMV / Venus Prime