* IdiotPlot: The plot of "Neutron Star" depends on pretty much every named character not expecting tidal forces around neutron stars, despite such forces being clearly understood in the 1960s, when the story was written.
** Although "Neutron Star" was retconned later in ''Crashlander'' and ''Juggler of Worlds'' to be a limited perspective on a deeper Puppeteer/ARM game where the only person not truly aware of the tidal force was Beowulf. It's still' pretty dumb of a pilot not to know this.
* ItsTheSameNowItSucks: There are two things preventing ''Fate of Worlds'' from being a satisfactory conclusion to the ''{{Ringworld}}'' series: Louis is mostly only a passive observer of events, just like he was in ''The Ringworld Throne'', and the ending is essentially the same as that of ''Ringworld's Children'' in that it involves [[spoiler:moving multiple-planet-sized objects through hyperspace to get away from attackers]].
* JumpTheShark: Ever since Carlos Wu's autodoc was introduced in "Procrustes", it became a {{MacGuffin}} that allows everybody who possesses it to solve all their problems with {{nanotechnology}}.
* MagnificentBastard: Ol't'ro.
* MarySue: Peace Corben from the Man-Kzin Wars stories, ''in spades''.
* UnfortunateImplications: There are an awful lot of species with non-sentient females.
** Justified in most cases, though. The Puppeteer "females" are actually a separate species that the puppeteers use to incubate fertilized eggs (in the same manner that predatory wasps will use a paralyzed caterpillar to incubate ''their eggs''), and the Kzinti had selectively bred for non-sentient females for several thousand years using genetic technology they stole from a more advance race.
*** Also, this comes back to bite the Kzin in the ass on more than one occasion, when they underestimate both Kzin and human females. So...Fortunate Implications?
** On the other hand, the Grog are a sentient alien species whose ''males'' are non-sentient.