diff --git a/src/genworld_gui.cpp b/src/genworld_gui.cpp
--- a/src/genworld_gui.cpp
+++ b/src/genworld_gui.cpp
@@ -588,7 +588,7 @@ struct GenerateLandscapeWindow : public 
 				break;
 
 			case GLAND_TERRAIN_PULLDOWN: {
-				byte old_gm = _game_mode;
+				GameMode old_gm = _game_mode;
 				_game_mode = GM_MENU;
 				IConsoleSetSetting("difficulty.terrain_type", index);
 				_game_mode = old_gm;
@@ -596,7 +596,7 @@ struct GenerateLandscapeWindow : public 
 			}
 
 			case GLAND_WATER_PULLDOWN: {
-				byte old_gm = _game_mode;
+				GameMode old_gm = _game_mode;
 				_game_mode = GM_MENU;
 				IConsoleSetSetting("difficulty.quantity_sea_lakes", index);
 				_game_mode = old_gm;
diff --git a/src/gfx.cpp b/src/gfx.cpp
--- a/src/gfx.cpp
+++ b/src/gfx.cpp
@@ -3,6 +3,7 @@
 /** @file gfx.cpp Handling of drawing text and other gfx related stuff. */
 
 #include "stdafx.h"
+#include "openttd.h"
 #include "gfx_func.h"
 #include "variables.h"
 #include "spritecache.h"
@@ -36,7 +37,7 @@ DrawPixelInfo _screen;
 bool _screen_disable_anim = false;   ///< Disable palette animation (important for 32bpp-anim blitter during giant screenshot)
 bool _exit_game;
 bool _networking;         ///< are we in networking mode?
-byte _game_mode;
+GameMode _game_mode;
 int8 _pause_game;
 int _pal_first_dirty;
 int _pal_count_dirty;
diff --git a/src/network/network_client.cpp b/src/network/network_client.cpp
--- a/src/network/network_client.cpp
+++ b/src/network/network_client.cpp
@@ -334,7 +334,7 @@ DEF_CLIENT_SEND_COMMAND_PARAM(PACKET_CLI
 //   DEF_CLIENT_RECEIVE_COMMAND has parameter: Packet *p
 // **********
 
-extern bool SafeSaveOrLoad(const char *filename, int mode, int newgm, Subdirectory subdir);
+extern bool SafeSaveOrLoad(const char *filename, int mode, GameMode newgm, Subdirectory subdir);
 extern StringID _switch_mode_errorstr;
 
 DEF_CLIENT_RECEIVE_COMMAND(PACKET_SERVER_FULL)
diff --git a/src/openttd.cpp b/src/openttd.cpp
--- a/src/openttd.cpp
+++ b/src/openttd.cpp
@@ -844,9 +844,9 @@ static void StartScenario()
  * @param newgm switch to this mode of loading fails due to some unknown error
  * @param subdir default directory to look for filename, set to 0 if not needed
  */
-bool SafeSaveOrLoad(const char *filename, int mode, int newgm, Subdirectory subdir)
+bool SafeSaveOrLoad(const char *filename, int mode, GameMode newgm, Subdirectory subdir)
 {
-	byte ogm = _game_mode;
+	GameMode ogm = _game_mode;
 
 	_game_mode = newgm;
 	assert(mode == SL_LOAD || mode == SL_OLD_LOAD);
diff --git a/src/openttd.h b/src/openttd.h
--- a/src/openttd.h
+++ b/src/openttd.h
@@ -5,10 +5,10 @@
 #ifndef OPENTTD_H
 #define OPENTTD_H
 
-enum GameModes {
+enum GameMode {
 	GM_MENU,
 	GM_NORMAL,
-	GM_EDITOR
+	GM_EDITOR,
 };
 
 enum SwitchModes {
@@ -35,7 +35,7 @@ enum {
 	DO_WAYPOINTS          = 6,
 };
 
-extern byte _game_mode;
+extern GameMode _game_mode;
 extern bool _exit_game;
 extern int8 _pause_game;
 
diff --git a/src/video/dedicated_v.cpp b/src/video/dedicated_v.cpp
--- a/src/video/dedicated_v.cpp
+++ b/src/video/dedicated_v.cpp
@@ -125,7 +125,7 @@ static void CloseWindowsConsoleThread()
 
 static void *_dedicated_video_mem;
 
-extern bool SafeSaveOrLoad(const char *filename, int mode, int newgm, Subdirectory subdir);
+extern bool SafeSaveOrLoad(const char *filename, int mode, GameMode newgm, Subdirectory subdir);
 extern void SwitchMode(int new_mode);
 
 static FVideoDriver_Dedicated iFVideoDriver_Dedicated;