diff --git a/assets.h b/assets.h
index ed417b8..8380ab5 100644
--- a/assets.h
+++ b/assets.h
@@ -2,6 +2,8 @@
 #define _LCR_ASSETS_H
 
 /**
+  Assets embedded in source code.
+
   NOTES:
   - All images are 64x64, stored in an indexed mode (8bits pery pixel), the
     image starts with a 256 color palette in RGB565 format (i.e. the palette
@@ -13,7 +15,7 @@
     the sky.
 */
 
-#include <stdint.h>
+#include "general.h"
 #include "map.h"
 
 static const char *LCR_texts[] =
diff --git a/debug.h b/debug.h
deleted file mode 100644
index 783143b..0000000
--- a/debug.h
+++ /dev/null
@@ -1,23 +0,0 @@
-#ifndef _LCR_DEBUG_H
-#define _LCR_DEBUG_H
-
-#include "map.h"
-#include <stdio.h>
-
-void LCR_debugPrintCurrentMap()
-{
-  puts("current map:");
-
-  for (int i = 0; i < LCR_currentMap.blockCount; ++i)
-  {
-    uint8_t x, y, z;
-
-    LCR_mapBlockGetCoords(LCR_currentMap.blocks + i * 4,&x,&y,&z);
-
-    printf("  block %d: type %x, coord %d (%d %d %d)\n",i,
-      LCR_currentMap.blocks[i * 4],LCR_mapBlockGetCoordNumber(
-      LCR_currentMap.blocks + i * 4),x,y,z);
-  }
-}
-
-#endif
diff --git a/frontend_sdl.c b/frontend_sdl.c
index 8fa4129..a536601 100644
--- a/frontend_sdl.c
+++ b/frontend_sdl.c
@@ -4,7 +4,6 @@
 #define LCR_SETTING_LOG_LEVEL 2
 
 #include "game.h"
-#include "debug.h"
 
 SDL_Window *window;
 SDL_Renderer *renderer;
diff --git a/game.h b/game.h
index 5da8d1f..2a42d54 100644
--- a/game.h
+++ b/game.h
@@ -1,3 +1,6 @@
+#ifndef _LCR_GAME_H
+#define _LCR_GAME_H
+
 /**
   game: this file implements the backend of a complete, actually playable
   game, and is meant to be included and used by specific frontends (which
@@ -42,9 +45,6 @@
   the map module) etc.
 */
 
-#ifndef _LCR_GAME_H
-#define _LCR_GAME_H
-
 #define LCR_KEY_UP    0x00
 #define LCR_KEY_RIGHT 0x01
 #define LCR_KEY_DOWN  0x02
@@ -195,9 +195,8 @@ void LCR_drawPixelXYUnsafe(unsigned int x, unsigned int y, uint16_t color);
 static inline void LCR_drawPixelXYSafe(unsigned int x, unsigned int y,
   uint_fast16_t color);
 
-#include "constants.h"
+#include "general.h"
 #include "racing.h"
-#include "settings.h"
 #include "audio.h"
 #include "assets.h"
 #include "renderer.h"
diff --git a/constants.h b/general.h
similarity index 80%
rename from constants.h
rename to general.h
index 0cdd2ca..8cce340 100644
--- a/constants.h
+++ b/general.h
@@ -1,8 +1,15 @@
-#ifndef _LCR_CONSTANTS_H
-#define _LCR_CONSTANTS_H
+#ifndef _LCR_GENERAL_H
+#define _LCR_GENERAL_H
 
+/**
+  General resources for all modules.
+*/
+
+#include <stdint.h>
 #include "settings.h"
 
+// constants (not supposed to be changed, doing so may break stuff):
+
 #define LCR_EFFECTIVE_RESOLUTION_X \
   (LCR_SETTING_RESOLUTION_X / LCR_SETTING_RESOLUTION_SUBDIVIDE)
 
@@ -41,4 +48,9 @@
 #define LCR_MENU_TABS 4
 #define LCR_MENU_STRING_SIZE 16
 
-#endif
+char _LCR_hexDigit(int i)
+{
+  return i < 10 ? '0' + i : ('a' - 10 + i);
+}
+
+#endif // guard
diff --git a/map.h b/map.h
index f656ce3..7387150 100644
--- a/map.h
+++ b/map.h
@@ -1,10 +1,6 @@
 #ifndef _LCR_MAP
 #define _LCR_MAP
 
-#include <stdint.h>
-#include "constants.h"
-#include "settings.h"
-
 /**
   The map (track) module for Licar.
 
@@ -56,6 +52,8 @@
         - last if C7 is set, the block is flipped vertically
 */
 
+#include "general.h"
+
 #define LCR_MAP_NAME_MAX_LEN          15   /**< Maximum map name length (without
                                              terminating zero. */
 #define LCR_BLOCK_START_CHAR          ':'
diff --git a/racing.h b/racing.h
index 7bbc479..4ee468b 100644
--- a/racing.h
+++ b/racing.h
@@ -1,3 +1,6 @@
+#ifndef _LCR_RACING_H
+#define _LCR_RACING_H
+
 /**
   Racing module: implements the racing physics and logic as well as replays and
   other related things.
@@ -19,9 +22,6 @@
     string will be ignored.
 */
 
-#ifndef _LCR_RACING_H
-#define _LCR_RACING_H
-
 typedef int32_t LCR_GameUnit;  ///< abstract game unit
 
 #define LCR_GAME_UNIT 1024     ///< length of map square in LCR_GameUnits
@@ -41,6 +41,7 @@ typedef int32_t LCR_GameUnit;  ///< abstract game unit
 #define TPE_RESHAPE_TENSION_LIMIT 3
 #define TPE_RESHAPE_ITERATIONS    8
 
+#include "general.h"
 #include "map.h"
 #include "tinyphysicsengine.h"
 
@@ -145,11 +146,6 @@ void LCR_replayInitPlaying(void)
   LCR_replay.currentFrame = 0;
 }
 
-char _LCR_hexDigit(int i)
-{
-  return i < 10 ? '0' + i : ('a' - 10 + i);
-}
-
 /**
   Outputs current replay using provided character printing function. The string
   will be zero terminated.
diff --git a/renderer.h b/renderer.h
index a945356..311f830 100644
--- a/renderer.h
+++ b/renderer.h
@@ -1,3 +1,6 @@
+#ifndef _LCR_RENDERER_H
+#define _LCR_RENDERER_H
+
 /**
   Renderer: implements 3D and 2D rendering.
 
@@ -12,9 +15,6 @@
     for far away areas with "something" we just draw some 2D rectangles.
 */
 
-#ifndef _LCR_RENDERER_H
-#define _LCR_RENDERER_H
-
 #define S3L_RESOLUTION_X LCR_SETTING_RESOLUTION_X
 #define S3L_RESOLUTION_Y LCR_SETTING_RESOLUTION_Y
 #define S3L_PIXEL_FUNCTION _LCR_pixelFunc3D
diff --git a/settings.h b/settings.h
index d14b282..6f1c42f 100644
--- a/settings.h
+++ b/settings.h
@@ -1,6 +1,11 @@
 #ifndef _LCR_SETTINGS_H
 #define _LCR_SETTINGS_H
 
+/**
+  Settings file, values here may be changed by the user or overriden by frontend
+  before compilation.
+*/
+
 #ifndef LCR_SETTING_RESOLUTION_X
   #define LCR_SETTING_RESOLUTION_X 1024
 #endif