Most two- and three-dimensional video games are examples of what computer scientists would call soft real-time interactive agent-based computer simulations. Let's break this phrase down in order to better understand what it means. In most video games, some subset of the real world -or an imaginary world- is modeled mathematically so that it can be manipulated by a computer.
The model is an approximation to and a simplification of
subnautica free reality (even if it's an imaginary reality), because it is clearly impractical to include every detail down to the level of atoms or quarks. Hence, the mathematical model is a simulation of the real or imagined game world. Approximation and simplification are two of the game developer's most powerful tools. When used skillfully, even a greatly simplified model can sometimes be almost indistinguishable from reality and a lot more fun.