These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Hollywood Science: How hard Orion's Arm's "hard sci-fi" actually is is debatable. The project has had critics attack it for unrealistic technological optimism, especially in fields like biology (the genetic code of complex organisms is extremely difficult to successfully re-engineer to the point where Artificial Humans may be more practical than enhancing real humans), and its implementation of transhumanism and "Singularity" (which has many skeptics and makes a lot of assumptions about the nature of intelligence and computers). The members of stardestroyer.net have produced some fairly comprehensive and hostile criticisms.
Inferred Holocaust: The Terragen Sphere and other civilizations continuously find the remains of prior civilizations, some of which spanned massive distances before simply disappearing. Something keeps wiping out all those galactic empires. Naturally this has gotten quite a few scientists worried about how long it will be before said mysterious force shows up to put down the Terragen Sphere...
Jerkass Woobie: The Bitenic Squids. They're all borderline sociopathic at best, but only because they're a horribly failed attempt at creating a clade that wouldn't be restrained by bias or solipsism.
Nightmare Fuel: The aptly-named Queen Of Pain. Take a furious, half-dead cat and uplift/enhance it over and over again until it's basically been warped into a madness-inducing Eldritch Abomination that loves to torture.
Spiritual Licensee: In terms of style, setting, and tone, the project has a lot of similarities to The Culture novels. Since there will doubtlessly be no further Culture books thanks to Author Existence Failure, this means that the series could be treated as a spiritual continuation of sorts.