diff --git a/Graphics/FreeGame/Backends/GLFW.hs b/Graphics/FreeGame/Backends/GLFW.hs
--- a/Graphics/FreeGame/Backends/GLFW.hs
+++ b/Graphics/FreeGame/Backends/GLFW.hs
@@ -1,3 +1,14 @@
+-----------------------------------------------------------------------------
+-- |
+-- Module      :  Graphics.FreeGame.Backends.GLFW
+-- Copyright   :  (C) 2013 Fumiaki Kinoshita
+-- License     :  BSD-style (see the file LICENSE)
+--
+-- Maintainer  :  Fumiaki Kinsohita <fumiexcel@gmail.com>
+-- Stability   :  experimental
+-- Portability :  non-portable
+--
+----------------------------------------------------------------------------
 {-# LANGUAGE ImplicitParams, ScopedTypeVariables #-}
 module Graphics.FreeGame.Backends.GLFW (runGame) where
 import Graphics.UI.GLFW as GLFW
diff --git a/Graphics/FreeGame/Base.hs b/Graphics/FreeGame/Base.hs
--- a/Graphics/FreeGame/Base.hs
+++ b/Graphics/FreeGame/Base.hs
@@ -2,7 +2,7 @@
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  Graphics.FreeGame.Base
--- Copyright   :  (C) 2012 Fumiaki Kinoshita
+-- Copyright   :  (C) 2012-2013 Fumiaki Kinoshita
 -- License     :  BSD-style (see the file LICENSE)
 --
 -- Maintainer  :  Fumiaki Kinsohita <fumiexcel@gmail.com>
diff --git a/Graphics/FreeGame/Data/Bitmap.hs b/Graphics/FreeGame/Data/Bitmap.hs
--- a/Graphics/FreeGame/Data/Bitmap.hs
+++ b/Graphics/FreeGame/Data/Bitmap.hs
@@ -1,7 +1,7 @@
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  Graphics.FreeGame.Data.Bitmap
--- Copyright   :  (C) 2012 Fumiaki Kinoshita
+-- Copyright   :  (C) 2013 Fumiaki Kinoshita
 -- License     :  BSD-style (see the file LICENSE)
 --
 -- Maintainer  :  Fumiaki Kinsohita <fumiexcel@gmail.com>
diff --git a/Graphics/FreeGame/Data/Color.hs b/Graphics/FreeGame/Data/Color.hs
--- a/Graphics/FreeGame/Data/Color.hs
+++ b/Graphics/FreeGame/Data/Color.hs
@@ -1,7 +1,7 @@
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  Graphics.FreeGame.Data.Color
--- Copyright   :  (C) 2012 Fumiaki Kinoshita
+-- Copyright   :  (C) 2013 Fumiaki Kinoshita
 -- License     :  BSD-style (see the file LICENSE)
 --
 -- Maintainer  :  Fumiaki Kinsohita <fumiexcel@gmail.com>
@@ -10,27 +10,40 @@
 --
 -- Colors and its operations
 ----------------------------------------------------------------------------
-module Graphics.FreeGame.Data.Color (Color(..), fromRGBA, colorAsWord8, transparent, white, black, red, green, blue, yellow, cyan, magenta, intermediate, halfD, halfB) where
+module Graphics.FreeGame.Data.Color (
+    -- * The type
+    Color(..)
+    , colorAsWord8
+    -- * Color operations
+    , transparent
+    , intermediate
+    , halfD
+    , halfB
+    -- * Basic colors
+    , white, black, red, green, blue, yellow, cyan, magenta
+    ) where
 
 import Data.Word
 
+-- | A color that has red, green, blue, alpha as its component.
 data Color = Color Float Float Float Float deriving (Show, Eq, Ord)
 
-fromRGBA :: Float -> Float -> Float -> Float -> Color
-fromRGBA = Color
-
 colorAsWord8 :: Color -> (Word8, Word8, Word8, Word8)
 colorAsWord8 (Color r g b a) = (floor $ r * 255, floor $ g * 255, floor $ b * 255, floor $ a * 255)
 
+-- | An intermediate between the given colors.
 intermediate :: Color -> Color -> Color
 intermediate (Color r0 g0 b0 a0) (Color r1 g1 b1 a1) = Color ((r0 + r1)/2) ((g0 + g1)/2) ((b0 + b1)/2) ((a0 + a1)/2)
 
+-- | Give a transparency to the color.
 transparent :: Float -> Color -> Color
 transparent f (Color r g b a) = Color r g b (f * a)
 
+-- | An intermediate between the black and the given color
 halfD :: Color -> Color
 halfD = intermediate black
 
+-- | An intermediate between the white and the given color
 halfB :: Color -> Color
 halfB = intermediate white
 
diff --git a/Graphics/FreeGame/Data/Font.hs b/Graphics/FreeGame/Data/Font.hs
--- a/Graphics/FreeGame/Data/Font.hs
+++ b/Graphics/FreeGame/Data/Font.hs
@@ -2,7 +2,7 @@
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  Graphics.FreeGame.Data.Font
--- Copyright   :  (C) 2012 Fumiaki Kinoshita
+-- Copyright   :  (C) 2013 Fumiaki Kinoshita
 -- License     :  BSD-style (see the file LICENSE)
 --
 -- Maintainer  :  Fumiaki Kinsohita <fumiexcel@gmail.com>
diff --git a/Graphics/FreeGame/Input.hs b/Graphics/FreeGame/Input.hs
--- a/Graphics/FreeGame/Input.hs
+++ b/Graphics/FreeGame/Input.hs
@@ -1,7 +1,19 @@
+-----------------------------------------------------------------------------
+-- |
+-- Module      :  Graphics.FreeGame.Input
+-- Copyright   :  (C) 2013 Fumiaki Kinoshita
+-- License     :  BSD-style (see the file LICENSE)
+--
+-- Maintainer  :  Fumiaki Kinsohita <fumiexcel@gmail.com>
+-- Stability   :  experimental
+-- Portability :  non-portable
+--
+----------------------------------------------------------------------------
 module Graphics.FreeGame.Input where
 
 import Data.Vect
 
+-- | The state of the mouse.
 data MouseState = MouseState
     { mousePosition :: Vec2
     , leftButton :: Bool
@@ -10,6 +22,7 @@
     , mouseWheel :: Int
     } deriving Show
 
+-- | Keys.
 data Key
         = KeyChar Char
         | KeySpace
diff --git a/Graphics/FreeGame/Simple.hs b/Graphics/FreeGame/Simple.hs
--- a/Graphics/FreeGame/Simple.hs
+++ b/Graphics/FreeGame/Simple.hs
@@ -1,7 +1,7 @@
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  Graphics.FreeGame.Simple
--- Copyright   :  (C) 2012 Fumiaki Kinoshita
+-- Copyright   :  (C) 2013 Fumiaki Kinoshita
 -- License     :  BSD-style (see the file LICENSE)
 --
 -- Maintainer  :  Fumiaki Kinsohita <fumiexcel@gmail.com>
@@ -15,6 +15,7 @@
     Game
 
     -- * Run the game
+    ,GameParam
     ,defaultGameParam
     ,runSimple
 
@@ -39,6 +40,7 @@
 
     -- * Utilities
     ,randomness
+    ,degrees
 
     -- * Reexports
     ,module Graphics.FreeGame.Input
diff --git a/Graphics/FreeGame/Util.hs b/Graphics/FreeGame/Util.hs
--- a/Graphics/FreeGame/Util.hs
+++ b/Graphics/FreeGame/Util.hs
@@ -2,7 +2,7 @@
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  Graphics.FreeGame.Util
--- Copyright   :  (C) 2012 Fumiaki Kinoshita
+-- Copyright   :  (C) 2013 Fumiaki Kinoshita
 -- License     :  BSD-style (see the file LICENSE)
 --
 -- Maintainer  :  Fumiaki Kinsohita <fumiexcel@gmail.com>
diff --git a/free-game.cabal b/free-game.cabal
--- a/free-game.cabal
+++ b/free-game.cabal
@@ -1,5 +1,5 @@
 name:                free-game
-version:             0.3.1.2
+version:             0.3.1.3
 synopsis:            Create graphical applications for free.
 description:         Cross-platform GUI library based on free monads.
 homepage:            https://github.com/fumieval/free-game
@@ -22,7 +22,7 @@
 
 source-repository head
   type: git
-  location: git@github.com:fumieval/free-game.git
+  location: https://github.com/fumieval/free-game.git
 
 library
   exposed-modules:     Graphics.FreeGame
