Rikchik Technology

Rikchik tech development was, for the most part, similar to humans. Certain things are missing, and certain things are new.

Missing things

The Wheel
Never came up: the lack of harnessable animals also had an effect. See Repulsion for why they don't miss it. Pulleys appeared at TL4, gears at TL5.
Gunpowder
The chemicals involved are not common: by the time it was synthesized, it was unnecessary. See Displacement.
Anything sound-related
Obviously, not as obvious for them as for us. They are aware that vibrations can be carried through the air, but not of the amount of information that can be gained through frequency analysis, etc.
Calculus
They get similar effects through math involving infinite series, but derivatives and integrals are foreign to them.
Radio Communication
They know how to do this (at TL6), but don't like to, as it tends to cause unpleasant effects in crystals that are usually very tasty. (Imagine if radio broadcasts made chocolate bitter.) Also, the lack of sound makes it less easily useful.
Winged Flight
No winged animals on Rigil 2, so no examples. There are buoyant (lighter-than-air) animals, and rikchiks learned how to do that very quickly (TL2).

New things

Repulsion (at TL2)
Certain substances (which occur naturally on Rigil 2), in certain shapes, push against gravity. This allows creation of hovering platforms, but they cannot easily be raised or lowered without destroying the repulsion effect, except by tying them to something. (Some amount of height control was developed at TL4.) Basic repulsion requires a strong radial gravity well, such as a planet.
Advanced repulsion (TL6, TL7) allows raising and lowering (using liquid forms of the repulsion alloys) and repulsion-driven horizontal movement, as well as repulsion within a spinning inertial-gravity environment. Repulsion will not work against inertia generated within an accelerating spaceship.
Displacement (at TL4)
Another strange chemical process, possibly related to Repulsion, by which 3 stones in a row become a particle beam on contact, consuming two of the stones. The discovery and understanding of this revolutionized rikchik warfare, much like Gunpowder did for humans.
Advanced understanding of the principles behind displacement (TL7) allows other effects, including nuclear fission.
Pathonic theory (at TL6)
Rikchiks can naturally "see" emotions: they have a pathonic detection organ. Some amount of pathonic theory existed at TL4, but true understanding of pathons and construction of artificial pathon detectors did not occur until TL6. The mass effects of pathons was known but the FTL travel implications escaped rikchik scientists until human contact.
Universal Language (at TL4)
The worldwide rikchik culture embraced a universal 2nd language in the post-golden age. Today all rikchiks speak this language, possibly in addition to a national language.
Rikchik stuff
RPG stuff