Write an overvview in docs

docs/source/index.rst

@@ -1,6 +1,23 @@
 Overview
 ========
 
+Brutal Maze is a thrilling shoot 'em up game with minimalist art style.
+
+.. image:: images/screenshot.png
+   :target: recplayer.html
+
+Notable features:
+
+* Being highly portable.
+* Auto-generated and infinite maze.
+* No binary data for drawing.
+* Enemies with special abilities: stun, poison, camo, etc.
+* Somewhat a realistic physic and logic system.
+* Resizable game window in-game.
+* Easily customizable via INI file format.
+* Recordable in JSON (some kind of silent screencast).
+* Remote control through TCP/IP socket (can be used in AI researching).
+
 Table of Contents
 -----------------