diff --git a/src/blitter/32bpp_anim.cpp b/src/blitter/32bpp_anim.cpp
index a9a464bf74466..6364be8266e3e 100644
--- a/src/blitter/32bpp_anim.cpp
+++ b/src/blitter/32bpp_anim.cpp
@@ -15,6 +15,7 @@
 
 #include "../safeguards.h"
 
+/** Instantiation of the 32bpp with animation blitter factory. */
 static FBlitter_32bppAnim iFBlitter_32bppAnim;
 
 template <BlitterMode mode>
diff --git a/src/blitter/32bpp_anim.hpp b/src/blitter/32bpp_anim.hpp
index 5967ea4025d1d..c3c6b172cdd1d 100644
--- a/src/blitter/32bpp_anim.hpp
+++ b/src/blitter/32bpp_anim.hpp
@@ -8,11 +8,12 @@
 #include "32bpp_optimized.hpp"
 #include "factory.hpp"
 
+/** The optimised 32 bpp blitter with palette animation. */
 class Blitter_32bppAnim : public Blitter_32bppOptimized {
 private:
-	uint8 *anim_buf; ///< In this buffer we keep track of the 8bpp indexes so we can do palette animation
-	int anim_buf_width;
-	int anim_buf_height;
+	uint8 *anim_buf;     ///< In this buffer we keep track of the 8bpp indexes so we can do palette animation
+	int anim_buf_width;  ///< The width of the animation buffer.
+	int anim_buf_height; ///< The height of the animation buffer.
 
 public:
 	Blitter_32bppAnim() :
@@ -38,6 +39,7 @@ class Blitter_32bppAnim : public Blitter_32bppOptimized {
 	template <BlitterMode mode> void Draw(const Blitter::BlitterParams *bp, ZoomLevel zoom);
 };
 
+/** Factory for the 32bpp blitter with animation. */
 class FBlitter_32bppAnim: public BlitterFactory<FBlitter_32bppAnim> {
 public:
 	/* virtual */ const char *GetName() { return "32bpp-anim"; }
diff --git a/src/blitter/32bpp_base.hpp b/src/blitter/32bpp_base.hpp
index 4a1b6f3b5b4aa..8335d04dc774c 100644
--- a/src/blitter/32bpp_base.hpp
+++ b/src/blitter/32bpp_base.hpp
@@ -8,12 +8,10 @@
 #include "base.hpp"
 #include "../core/bitmath_func.hpp"
 
+/** Base for all 32bpp blitters. */
 class Blitter_32bppBase : public Blitter {
 public:
 	/* virtual */ uint8 GetScreenDepth() { return 32; }
-//	/* virtual */ void Draw(Blitter::BlitterParams *bp, BlitterMode mode, ZoomLevel zoom);
-//	/* virtual */ void DrawColourMappingRect(void *dst, int width, int height, PaletteID pal);
-//	/* virtual */ Sprite *Encode(SpriteLoader::Sprite *sprite, AllocatorProc *allocator);
 	/* virtual */ void *MoveTo(const void *video, int x, int y);
 	/* virtual */ void SetPixel(void *video, int x, int y, uint8 color);
 	/* virtual */ void DrawRect(void *video, int width, int height, uint8 color);
diff --git a/src/blitter/32bpp_optimized.cpp b/src/blitter/32bpp_optimized.cpp
index 1fd4f7a5c0fe5..ac6e7d099f0c3 100644
--- a/src/blitter/32bpp_optimized.cpp
+++ b/src/blitter/32bpp_optimized.cpp
@@ -12,6 +12,7 @@
 
 #include "../safeguards.h"
 
+/** Instantiation of the optimized 32bpp blitter factory. */
 static FBlitter_32bppOptimized iFBlitter_32bppOptimized;
 
 /**
diff --git a/src/blitter/32bpp_optimized.hpp b/src/blitter/32bpp_optimized.hpp
index 4d6fb9dfd8ddf..67f63e39a8f7f 100644
--- a/src/blitter/32bpp_optimized.hpp
+++ b/src/blitter/32bpp_optimized.hpp
@@ -8,11 +8,13 @@
 #include "32bpp_simple.hpp"
 #include "factory.hpp"
 
+/** The optimised 32 bpp blitter (without palette animation). */
 class Blitter_32bppOptimized : public Blitter_32bppSimple {
 public:
+	/** Data stored about a (single) sprite. */
 	struct SpriteData {
-		uint32 offset[ZOOM_LVL_COUNT][2];
-		byte data[VARARRAY_SIZE];
+		uint32 offset[ZOOM_LVL_COUNT][2]; ///< Offsets (from .data) to streams for different zoom levels, and the normal and remap image information.
+		byte data[VARARRAY_SIZE];         ///< Data, all zoomlevels.
 	};
 
 	/* virtual */ void Draw(Blitter::BlitterParams *bp, BlitterMode mode, ZoomLevel zoom);
@@ -23,6 +25,7 @@ class Blitter_32bppOptimized : public Blitter_32bppSimple {
 	template <BlitterMode mode> void Draw(const Blitter::BlitterParams *bp, ZoomLevel zoom);
 };
 
+/** Factory for the optimised 32 bpp blitter (without palette animation). */
 class FBlitter_32bppOptimized: public BlitterFactory<FBlitter_32bppOptimized> {
 public:
 	/* virtual */ const char *GetName() { return "32bpp-optimized"; }
diff --git a/src/blitter/32bpp_simple.cpp b/src/blitter/32bpp_simple.cpp
index 46e1371ac9d8f..0335d75ddd6bf 100644
--- a/src/blitter/32bpp_simple.cpp
+++ b/src/blitter/32bpp_simple.cpp
@@ -12,6 +12,7 @@
 
 #include "../safeguards.h"
 
+/** Instantiation of the simple 32bpp blitter factory. */
 static FBlitter_32bppSimple iFBlitter_32bppSimple;
 
 void Blitter_32bppSimple::Draw(Blitter::BlitterParams *bp, BlitterMode mode, ZoomLevel zoom)
diff --git a/src/blitter/32bpp_simple.hpp b/src/blitter/32bpp_simple.hpp
index 059bb139498b9..8142bb889b30c 100644
--- a/src/blitter/32bpp_simple.hpp
+++ b/src/blitter/32bpp_simple.hpp
@@ -8,6 +8,7 @@
 #include "32bpp_base.hpp"
 #include "factory.hpp"
 
+/** The most trivial 32 bpp blitter (without palette animation). */
 class Blitter_32bppSimple : public Blitter_32bppBase {
 public:
 	/* virtual */ void Draw(Blitter::BlitterParams *bp, BlitterMode mode, ZoomLevel zoom);
@@ -17,6 +18,7 @@ class Blitter_32bppSimple : public Blitter_32bppBase {
 	/* virtual */ const char *GetName() { return "32bpp-simple"; }
 };
 
+/** Factory for the simple 32 bpp blitter. */
 class FBlitter_32bppSimple: public BlitterFactory<FBlitter_32bppSimple> {
 public:
 	/* virtual */ const char *GetName() { return "32bpp-simple"; }
diff --git a/src/blitter/8bpp_base.hpp b/src/blitter/8bpp_base.hpp
index dfe7e2b91a874..15b4cd9f6f05e 100644
--- a/src/blitter/8bpp_base.hpp
+++ b/src/blitter/8bpp_base.hpp
@@ -7,12 +7,11 @@
 
 #include "base.hpp"
 
+/** Base for all 8bpp blitters. */
 class Blitter_8bppBase : public Blitter {
 public:
 	/* virtual */ uint8 GetScreenDepth() { return 8; }
-//	/* virtual */ void Draw(Blitter::BlitterParams *bp, BlitterMode mode, ZoomLevel zoom);
 	/* virtual */ void DrawColourMappingRect(void *dst, int width, int height, PaletteID pal);
-//	/* virtual */ Sprite *Encode(SpriteLoader::Sprite *sprite, AllocatorProc *allocator);
 	/* virtual */ void *MoveTo(const void *video, int x, int y);
 	/* virtual */ void SetPixel(void *video, int x, int y, uint8 color);
 	/* virtual */ void DrawRect(void *video, int width, int height, uint8 color);
diff --git a/src/blitter/8bpp_debug.cpp b/src/blitter/8bpp_debug.cpp
index 374a1df31a5d3..d411173b527e6 100644
--- a/src/blitter/8bpp_debug.cpp
+++ b/src/blitter/8bpp_debug.cpp
@@ -7,6 +7,7 @@
 #include "../core/random_func.hpp"
 #include "8bpp_debug.hpp"
 
+/** Instantiation of the 8bpp debug blitter factory. */
 static FBlitter_8bppDebug iFBlitter_8bppDebug;
 
 void Blitter_8bppDebug::Draw(Blitter::BlitterParams *bp, BlitterMode mode, ZoomLevel zoom)
diff --git a/src/blitter/8bpp_debug.hpp b/src/blitter/8bpp_debug.hpp
index 6c30bc61eb727..5dd7548a4bd70 100644
--- a/src/blitter/8bpp_debug.hpp
+++ b/src/blitter/8bpp_debug.hpp
@@ -8,6 +8,7 @@
 #include "8bpp_base.hpp"
 #include "factory.hpp"
 
+/** 8bpp debug blitter; colours each sprite differently. */
 class Blitter_8bppDebug : public Blitter_8bppBase {
 public:
 	/* virtual */ void Draw(Blitter::BlitterParams *bp, BlitterMode mode, ZoomLevel zoom);
@@ -16,6 +17,7 @@ class Blitter_8bppDebug : public Blitter_8bppBase {
 	/* virtual */ const char *GetName() { return "8bpp-debug"; }
 };
 
+/** Factory for the 8bpp debug blitter. */
 class FBlitter_8bppDebug: public BlitterFactory<FBlitter_8bppDebug> {
 public:
 	/* virtual */ const char *GetName() { return "8bpp-debug"; }
diff --git a/src/blitter/8bpp_optimized.cpp b/src/blitter/8bpp_optimized.cpp
index 883a8aee917a5..761192ee1ed11 100644
--- a/src/blitter/8bpp_optimized.cpp
+++ b/src/blitter/8bpp_optimized.cpp
@@ -11,6 +11,7 @@
 
 #include "../safeguards.h"
 
+/** Instantiation of the 8bpp optimised blitter factory. */
 static FBlitter_8bppOptimized iFBlitter_8bppOptimized;
 
 void Blitter_8bppOptimized::Draw(Blitter::BlitterParams *bp, BlitterMode mode, ZoomLevel zoom)
diff --git a/src/blitter/8bpp_optimized.hpp b/src/blitter/8bpp_optimized.hpp
index 9d46624ad4aee..6bd0dc4e28301 100644
--- a/src/blitter/8bpp_optimized.hpp
+++ b/src/blitter/8bpp_optimized.hpp
@@ -8,11 +8,13 @@
 #include "8bpp_base.hpp"
 #include "factory.hpp"
 
+/** 8bpp blitter optimised for speed. */
 class Blitter_8bppOptimized : public Blitter_8bppBase {
 public:
+	/** Data stored about a (single) sprite. */
 	struct SpriteData {
-		uint32 offset[ZOOM_LVL_COUNT]; ///< offsets (from .data) to streams for different zoom levels
-		byte data[VARARRAY_SIZE];      ///< data, all zoomlevels
+		uint32 offset[ZOOM_LVL_COUNT]; ///< Offsets (from .data) to streams for different zoom levels.
+		byte data[VARARRAY_SIZE];      ///< Data, all zoomlevels.
 	};
 
 	/* virtual */ void Draw(Blitter::BlitterParams *bp, BlitterMode mode, ZoomLevel zoom);
@@ -21,6 +23,7 @@ class Blitter_8bppOptimized : public Blitter_8bppBase {
 	/* virtual */ const char *GetName() { return "8bpp-optimized"; }
 };
 
+/** Factory for the 8bpp blitter optimised for speed. */
 class FBlitter_8bppOptimized: public BlitterFactory<FBlitter_8bppOptimized> {
 public:
 	/* virtual */ const char *GetName() { return "8bpp-optimized"; }
diff --git a/src/blitter/8bpp_simple.cpp b/src/blitter/8bpp_simple.cpp
index 9166fc929f6e0..dd8fc145a421e 100644
--- a/src/blitter/8bpp_simple.cpp
+++ b/src/blitter/8bpp_simple.cpp
@@ -8,6 +8,7 @@
 
 #include "../safeguards.h"
 
+/** Instantiation of the simple 8bpp blitter factory. */
 static FBlitter_8bppSimple iFBlitter_8bppSimple;
 
 void Blitter_8bppSimple::Draw(Blitter::BlitterParams *bp, BlitterMode mode, ZoomLevel zoom)
diff --git a/src/blitter/8bpp_simple.hpp b/src/blitter/8bpp_simple.hpp
index 5624c9c7f88fd..8cacc93878bc2 100644
--- a/src/blitter/8bpp_simple.hpp
+++ b/src/blitter/8bpp_simple.hpp
@@ -8,6 +8,7 @@
 #include "8bpp_base.hpp"
 #include "factory.hpp"
 
+/** Most trivial 8bpp blitter. */
 class Blitter_8bppSimple : public Blitter_8bppBase {
 public:
 	/* virtual */ void Draw(Blitter::BlitterParams *bp, BlitterMode mode, ZoomLevel zoom);
@@ -16,6 +17,7 @@ class Blitter_8bppSimple : public Blitter_8bppBase {
 	/* virtual */ const char *GetName() { return "8bpp-simple"; }
 };
 
+/** Factory for the most trivial 8bpp blitter. */
 class FBlitter_8bppSimple: public BlitterFactory<FBlitter_8bppSimple> {
 public:
 	/* virtual */ const char *GetName() { return "8bpp-simple"; }
diff --git a/src/blitter/base.cpp b/src/blitter/base.cpp
index d8e33cedec589..1e6afdad518e2 100644
--- a/src/blitter/base.cpp
+++ b/src/blitter/base.cpp
@@ -13,18 +13,6 @@
 #include "base.hpp"
 #include "../core/math_func.hpp"
 
-/**
- * Draw a line with a given colour.
- * @param video The destination pointer (video-buffer).
- * @param x The x coordinate from where the line starts.
- * @param y The y coordinate from where the line starts.
- * @param x2 The x coordinate to where the line goes.
- * @param y2 The y coordinate to where the lines goes.
- * @param screen_width The width of the screen you are drawing in (to avoid buffer-overflows).
- * @param screen_height The height of the screen you are drawing in (to avoid buffer-overflows).
- * @param colour A 8bpp mapping colour.
- * @param width Line width.
- */
 void Blitter::DrawLine(void *video, int x, int y, int x2, int y2, int screen_width, int screen_height, uint8 colour, int width)
 {
 	int dy;
diff --git a/src/blitter/base.hpp b/src/blitter/base.hpp
index d57e26df970e6..59671159052a2 100644
--- a/src/blitter/base.hpp
+++ b/src/blitter/base.hpp
@@ -9,10 +9,11 @@
 #include "../spriteloader/spriteloader.hpp"
 #include "../zoom_type.h"
 
+/** The modes of blitting we can do. */
 enum BlitterMode {
-	BM_NORMAL,
-	BM_COLOUR_REMAP,
-	BM_TRANSPARENT,
+	BM_NORMAL,       ///< Perform the simple blitting.
+	BM_COLOUR_REMAP, ///< Perform a colour remapping.
+	BM_TRANSPARENT,  ///< Perform transparency colour remapping.
 };
 
 /**
@@ -20,20 +21,25 @@ enum BlitterMode {
  */
 class Blitter {
 public:
+	/** Parameters related to blitting. */
 	struct BlitterParams {
-		const void *sprite;      ///< Pointer to the sprite how ever the encoder stored it
-		const byte *remap;       ///< XXX -- Temporary storage for remap array
-
-		int skip_left, skip_top; ///< How much pixels of the source to skip on the left and top (based on zoom of dst)
-		int width, height;       ///< The width and height in pixels that needs to be drawn to dst
-		int sprite_width;        ///< Real width of the sprite
-		int sprite_height;       ///< Real height of the sprite
-		int left, top;           ///< The offset in the 'dst' in pixels to start drawing
-
-		void *dst;               ///< Destination buffer
-		int pitch;               ///< The pitch of the destination buffer
+		const void *sprite; ///< Pointer to the sprite how ever the encoder stored it
+		const byte *remap;  ///< XXX -- Temporary storage for remap array
+
+		int skip_left;      ///< How much pixels of the source to skip on the left (based on zoom of dst)
+		int skip_top;       ///< How much pixels of the source to skip on the top (based on zoom of dst)
+		int width;          ///< The width in pixels that needs to be drawn to dst
+		int height;         ///< The height in pixels that needs to be drawn to dst
+		int sprite_width;   ///< Real width of the sprite
+		int sprite_height;  ///< Real height of the sprite
+		int left;           ///< The left offset in the 'dst' in pixels to start drawing
+		int top;            ///< The top offset in the 'dst' in pixels to start drawing
+
+		void *dst;          ///< Destination buffer
+		int pitch;          ///< The pitch of the destination buffer
 	};
 
+	/** Types of palette animation. */
 	enum PaletteAnimation {
 		PALETTE_ANIMATION_NONE,           ///< No palette animation
 		PALETTE_ANIMATION_VIDEO_BACKEND,  ///< Palette animation should be done by video backend (8bpp only!)
@@ -104,9 +110,9 @@ class Blitter {
 	 * @param screen_width The width of the screen you are drawing in (to avoid buffer-overflows).
 	 * @param screen_height The height of the screen you are drawing in (to avoid buffer-overflows).
 	 * @param colour A 8bpp mapping colour.
-	 * @param width The width of line to draw.
+	 * @param width Line width.
 	 */
-	void DrawLine(void *video, int x, int y, int x2, int y2, int screen_width, int screen_height, uint8 colour, int width);
+	virtual void DrawLine(void *video, int x, int y, int x2, int y2, int screen_width, int screen_height, uint8 colour, int width);
 
 	/**
 	 * Copy from a buffer to the screen.
diff --git a/src/blitter/factory.hpp b/src/blitter/factory.hpp
index c9650a7b40dbd..46d12f9c9ec77 100644
--- a/src/blitter/factory.hpp
+++ b/src/blitter/factory.hpp
@@ -19,7 +19,7 @@ bool QZ_CanDisplay8bpp();
  */
 class BlitterFactoryBase {
 private:
-	const char *name;
+	const char *name; ///< The name of the blitter factory.
 
 	struct StringCompare {
 		bool operator () (const char *a, const char *b) const
@@ -28,14 +28,22 @@ class BlitterFactoryBase {
 		}
 	};
 
-	typedef std::map<const char *, BlitterFactoryBase *, StringCompare> Blitters;
+	typedef std::map<const char *, BlitterFactoryBase *, StringCompare> Blitters; ///< Map of blitter factories.
 
+	/**
+	 * Get the map with currently known blitters.
+	 * @return The known blitters.
+	 */
 	static Blitters &GetBlitters()
 	{
 		static Blitters &s_blitters = *new Blitters();
 		return s_blitters;
 	}
 
+	/**
+	 * Get the currently active blitter.
+	 * @return The currently active blitter.
+	 */
 	static Blitter **GetActiveBlitter()
 	{
 		static Blitter *s_blitter = NULL;
@@ -123,7 +131,12 @@ class BlitterFactoryBase {
 		return *GetActiveBlitter();
 	}
 
-
+	/**
+	 * Fill a buffer with information about the blitters.
+	 * @param p The buffer to fill.
+	 * @param last The last element of the buffer.
+	 * @return p The location till where we filled the buffer.
+	 */
 	static char *GetBlittersInfo(char *p, const char *last)
 	{
 		p += seprintf(p, last, "List of blitters:\n");
diff --git a/src/blitter/null.cpp b/src/blitter/null.cpp
index 335c6f8100e6a..916a9db1b9d81 100644
--- a/src/blitter/null.cpp
+++ b/src/blitter/null.cpp
@@ -7,6 +7,7 @@
 
 #include "../safeguards.h"
 
+/** Instantiation of the null blitter factory. */
 static FBlitter_Null iFBlitter_Null;
 
 Sprite *Blitter_Null::Encode(SpriteLoader::Sprite *sprite, AllocatorProc *allocator)
diff --git a/src/blitter/null.hpp b/src/blitter/null.hpp
index d234660a5c3de..f52ce7d504cf3 100644
--- a/src/blitter/null.hpp
+++ b/src/blitter/null.hpp
@@ -8,6 +8,7 @@
 #include "base.hpp"
 #include "factory.hpp"
 
+/** Blitter that does nothing. */
 class Blitter_Null : public Blitter {
 public:
 	/* virtual */ uint8 GetScreenDepth() { return 0; }
@@ -15,9 +16,9 @@ class Blitter_Null : public Blitter {
 	/* virtual */ void DrawColourMappingRect(void *dst, int width, int height, PaletteID pal) {};
 	/* virtual */ Sprite *Encode(SpriteLoader::Sprite *sprite, AllocatorProc *allocator);
 	/* virtual */ void *MoveTo(const void *video, int x, int y) { return NULL; };
-	/* virtual */ void SetPixel(void *video, int x, int y, uint8 color) {};
-	/* virtual */ void DrawRect(void *video, int width, int height, uint8 color) {};
-	/* virtual */ void DrawLine(void *video, int x, int y, int x2, int y2, int screen_width, int screen_height, uint8 color) {};
+	/* virtual */ void SetPixel(void *video, int x, int y, uint8 colour) {};
+	/* virtual */ void DrawRect(void *video, int width, int height, uint8 colour) {};
+	/* virtual */ void DrawLine(void *video, int x, int y, int x2, int y2, int screen_width, int screen_height, uint8 colour, int width) {};
 	/* virtual */ void CopyFromBuffer(void *video, const void *src, int width, int height) {};
 	/* virtual */ void CopyToBuffer(const void *video, void *dst, int width, int height) {};
 	/* virtual */ void CopyImageToBuffer(const void *video, void *dst, int width, int height, int dst_pitch) {};
@@ -29,6 +30,7 @@ class Blitter_Null : public Blitter {
 	/* virtual */ const char *GetName() { return "null"; }
 };
 
+/** Factory for the blitter that doesn nothing. */
 class FBlitter_Null: public BlitterFactory<FBlitter_Null> {
 public:
 	/* virtual */ const char *GetName() { return "null"; }
diff --git a/src/driver.cpp b/src/driver.cpp
index 6bcba25b9f16c..2011e6b524a63 100644
--- a/src/driver.cpp
+++ b/src/driver.cpp
@@ -13,19 +13,19 @@
 
 #include "safeguards.h"
 
-VideoDriver *_video_driver;
-char *_ini_videodriver;
-int _num_resolutions;
-uint16 _resolutions[32][2];
-uint16 _cur_resolution[2];
+VideoDriver *_video_driver; ///< The currently active video driver.
+char *_ini_videodriver;     ///< The video driver a stored in the configuration file.
+int _num_resolutions;       ///< The number of resolutions.
+uint16 _resolutions[32][2]; ///< List of resolutions.
+uint16 _cur_resolution[2];  ///< The current resolution.
 
-SoundDriver *_sound_driver;
-char *_ini_sounddriver;
+SoundDriver *_sound_driver; ///< The currently active sound driver.
+char *_ini_sounddriver;     ///< The sound driver a stored in the configuration file.
 
-MusicDriver *_music_driver;
-char *_ini_musicdriver;
+MusicDriver *_music_driver; ///< The currently active music driver.
+char *_ini_musicdriver;     ///< The music driver a stored in the configuration file.
 
-char *_ini_blitter;
+char *_ini_blitter;         ///< The blitter as stored in the configuration file.
 
 static const char* GetDriverParam(const char* const* parm, const char* name)
 {