A lot of this code is decompiled from the original java version, and those are names the decompiler assigned to the variables. Much of the code is extremely obfuscated due to what are probably compiler optimizations, and some variables have not been deciphered and renamed yet. This is why they mostly appear in the `gameLoop` function.
The game uses a 3D voxel raycaster to render things, which is a lot slower than more traditional methods of rendering. Luckily, C provides more powerful ways to optimize something like this than Java - and optimizations will keep coming.
I plan to port over a lot of user interface features, controls, and gameplay mechanics from the official game. However, this game will be taken in its own direction content-wise. For example, crafting will be a part of the game eventually, but creepers will not. New features will be added if they fit with the aesthetic and feel of the game, and make sense from a technichal and gameplay perspective.