The bottom 16 blocks of the world are made of a 1 block thick layer of bedrock and a 15 block deep sea of exotic fluid ; this also functions as the exit of the dimension once you have reached 6 attunement

Opalium / catalyst is a pink crystalline ore that generates at any height in the Liminus dimension.

Exotic crystal stalagmites generate at any Y level in liminus and can be smelted into exotic crystal

Exotic crystal stalactites generate on the ceiling at any Y level in liminus and can be smelted into exotic crystal

Chains will rarely generate connecting the ceiling and floor of caves.

Liminus's terrain contains many sheer drops down holes that can easily be over 100 blocks deep.

the surface terrain of liminus is incredibly jagged and hard to navigate.