GUI.

We all remember this:

Since there are some irrelevant parts, I modified it a bit, but left the watermark:

 Added the stats/skill tab:

 Added a belt:

Face merging, significantly improving frame rate. From 350 to 2300 FPS.
In a 15x2x15 map: from 20 to 100-160 FPS.

Work still in progress.

Update: Fixed bugs, works like a charm.

Mountain/Lake generation algorithm. Two parameters shapes the mountain's slope.

There is something messy  here.