The game uses cellular automation to simulate its world. Liquids flow, gases spread, boulders roll, fires spread, plants grow and walls crack and crumble. Other games, notably three that involve exploring underground caverns, use CA techniques: the classic Atari 800 puzzle game Boulder Dash (which directly inspired the behavior of the boulders here), and the recent indie hits Dwarf Fortress and Minecraft. Another game that bears some similarity, at least in the operation of its engine, is the “Falling Sand” Java game. However, In Profundis’ CA system will be rather more complex than most of these (except maybe for Dwarf Fortress — Tarn Adams is a genius). The fact that it’s 2D helps in this regard; it greatly decreases the amount of calculation needed for each frame.
The developer posted a YouTube video demonstrating his vision for the game: