Updated screenshot and added a few demo descriptions

README.md

@@ -3,7 +3,8 @@ Voxel game demos (Godot Engine)
 
 This project contains several scenes to test and demo the voxel module I'm developping for Godot Engine.
 
-![Screenshot](screenshots/2016_04_27_2037_half.png)
+![Screenshot](screenshots/2020_05_05_1953_small.png)
+
 
 Dependencies
 ---------------
@@ -13,3 +14,10 @@ This project uses a C++ module:
 
 For the old (unmaintained) pure-GDScript version, checkout the branch `full_gdscript`.
 
+
+Runnable scenes
+-----------------
+
+- `blocky_game/blocky_game.tscn`: sort of Minecraft clone with random features.
+- `blocky_terrain/main.tscn`: simple test for blocky terrain
+- `smooth_terrain/main.tscn`: simple test for Transvoxel smooth terrain