diff --git a/code/aliens.cpp b/code/aliens.cpp
index ef9df88..b79f6ba 100644
--- a/code/aliens.cpp
+++ b/code/aliens.cpp
@@ -26,19 +26,19 @@ object enemy[MAX_ALIENS];
 static bool placeAlien(object *theEnemy)
 {
 	if (rand() % 2 == 0)
-		theEnemy->x = rrand(800, 1600);
+		theEnemy->x = rrand(screen->w, screen->w * 2);
 	else
-		theEnemy->x = rrand(-800, 0);
+		theEnemy->x = rrand(-screen->w, 0);
 
 	if (rand() % 2 == 0)
-		theEnemy->y = rrand(600, 1200);
+		theEnemy->y = rrand(screen->h, screen->h * 2);
 	else
-		theEnemy->y = rrand(-600, 0);
+		theEnemy->y = rrand(-screen->h, 0);
 
 	if (currentGame.area == 24)
 	{
-		theEnemy->x = 800;
-		theEnemy->y = rrand(200, 400);
+		theEnemy->x = screen->w;
+		theEnemy->y = rrand((int)((1/3) * screen->h), (int)((2/3) * screen->h));
 	}
 
 	for (int i = 0 ; i < MAX_ALIENS ; i++)
@@ -396,8 +396,8 @@ static void getPreDefinedAliens()
 	if (currentGame.area == 5)
 	{
 		enemy[WC_BOSS].target = &player;
-		enemy[WC_BOSS].x = -400;
-		enemy[WC_BOSS].y = 300;
+		enemy[WC_BOSS].x = (int)(-screen->w / 2);
+		enemy[WC_BOSS].y = (int)(screen->h / 2);
 
 		enemy[13].owner = &enemy[WC_BOSS];
 		enemy[13].target = &player;
@@ -412,8 +412,8 @@ static void getPreDefinedAliens()
 	else if ((currentGame.area == 11) || (currentGame.area == 14))
 	{
 		enemy[WC_BOSS].target = &player;
-		enemy[WC_BOSS].x = -400;
-		enemy[WC_BOSS].y = 300;
+		enemy[WC_BOSS].x = (int)(-screen->w / 2);
+		enemy[WC_BOSS].y = (int)(screen->h / 2);
 
 		enemy[13].owner = &enemy[WC_BOSS];
 		enemy[13].target = &player;
@@ -475,14 +475,14 @@ static void addFriendly(int type)
 	enemy[type].active = true;
 
 	if (rand() % 2 == 0)
-		enemy[type].x = rrand(400, 550);
+		enemy[type].x = rrand((int)(screen->w / 2), (int)(screen->w / 2) + 150);
 	else
-		enemy[type].x = rrand(250, 400);
+		enemy[type].x = rrand((int)(screen->w / 2) - 150, (int)(screen->w / 2));
 
 	if (rand() % 2 == 0)
-		enemy[type].y = rrand(300, 450);
+		enemy[type].y = rrand((int)(screen->h / 2), (int)(screen->h / 2) + 150);
 	else
-		enemy[type].y = rrand(150, 300);
+		enemy[type].y = rrand((int)(screen->h / 2) - 150, (int)(screen->h / 2));
 
 	if (type == FR_PHOEBE)
 		enemy[type].classDef = CD_PHOEBE;
@@ -596,8 +596,8 @@ void initAliens()
 	{
 		enemy[WC_KLINE].flags |= FL_IMMORTAL | FL_NOFIRE | FL_NOMOVE;
 
-		enemy[WC_KLINE].x = 600;
-		enemy[WC_KLINE].y = 300;
+		enemy[WC_KLINE].x = (int)(screen->w * (2 / 3));
+		enemy[WC_KLINE].y = (int)(screen->h / 2);
 
 		enemy[WC_KLINE].deathCounter = -250;
 		enemy[WC_KLINE].maxShield = 1500;
@@ -1188,7 +1188,7 @@ void doAliens()
 
 				limitCharAdd(&theEnemy->hit, -1, 0, 100);
 
-				if ((theEnemy->x + theEnemy->image[0]->w > 0) && (theEnemy->x < 800) && (theEnemy->y + theEnemy->image[0]->h > 0) && (theEnemy->y < 600))
+				if ((theEnemy->x + theEnemy->image[0]->w > 0) && (theEnemy->x < screen->w) && (theEnemy->y + theEnemy->image[0]->h > 0) && (theEnemy->y < screen->h))
 				{
 					if ((!(theEnemy->flags & FL_DISABLED)) && (theEnemy->classDef != CD_ASTEROID) && (theEnemy->classDef != CD_ASTEROID2))
 						addEngine(theEnemy);
@@ -1207,7 +1207,7 @@ void doAliens()
 			else
 			{
 				theEnemy->shield--;
-				if ((theEnemy->x > 0) && (theEnemy->x < 800) && (theEnemy->y > 0) && (theEnemy->y < 600))
+				if ((theEnemy->x > 0) && (theEnemy->x < screen->w) && (theEnemy->y > 0) && (theEnemy->y < screen->h))
 				{
 					blit(theEnemy->image[theEnemy->face], (int)theEnemy->x, (int)theEnemy->y);
 					addExplosion(theEnemy->x + (rand() % theEnemy->image[0]->w), theEnemy->y + (rand() % theEnemy->image[0]->h), E_BIG_EXPLOSION);
diff --git a/code/defs.h b/code/defs.h
index 8cc6d12..e093b2f 100644
--- a/code/defs.h
+++ b/code/defs.h
@@ -305,3 +305,8 @@ extern const char *systemNames[];
 extern const char *systemBackground[];
 
 static const signed char rate2reload[6] = {15, 15, 13, 11, 9, 7};
+
+const int screenWidth = 800;
+const int screenHeight = 600;
+
+const int viewBorder = 100;
diff --git a/code/game.cpp b/code/game.cpp
index e05332c..d1c9f2c 100644
--- a/code/game.cpp
+++ b/code/game.cpp
@@ -233,7 +233,7 @@ int mainGameLoop()
 
 		if (engine.paused)
 		{
-			textSurface(22, "PAUSED", -1, 300, FONT_WHITE);
+			textSurface(22, "PAUSED", -1, (int)(screen->h / 2), FONT_WHITE);
 			blitText(22);
 			updateScreen();
 
diff --git a/code/graphics.cpp b/code/graphics.cpp
index 8260b00..8e79677 100644
--- a/code/graphics.cpp
+++ b/code/graphics.cpp
@@ -718,8 +718,8 @@ void doStarfield()
 		else if (star[i].speed == 1)
 			color = darkGrey;
 
-		wrapFloat(&(star[i].x += (engine.ssx * star[i].speed)), 0, 799);
-		wrapFloat(&(star[i].y += (engine.ssy * star[i].speed)), 0, 599);
+		wrapFloat(&(star[i].x += (engine.ssx * star[i].speed)), 0, screen->w - 1);
+		wrapFloat(&(star[i].y += (engine.ssy * star[i].speed)), 0, screen->h - 1);
 
 		putpixel(screen, (int)star[i].x, (int)star[i].y, color);
 		r.x = (int)star[i].x;
diff --git a/code/init.cpp b/code/init.cpp
index 31ce70e..28f052e 100644
--- a/code/init.cpp
+++ b/code/init.cpp
@@ -34,10 +34,10 @@ void initVars()
 {
 	srand(time(NULL));
 
-	for (int i = 0 ; i < 200 ; i++)
+	for (int i = 0 ; i < (int)(screen->w * screen->h / 2400) ; i++)
 	{
-		star[i].x = rand() % 800;
-		star[i].y = rand() % 600;
+		star[i].x = rand() % screen->w;
+		star[i].y = rand() % screen->h;
 		star[i].speed = 1 + (rand() % 3);
 	}
 
@@ -188,12 +188,12 @@ void initSystem()
 	SDL_WM_SetIcon(loadImage("gfx/alienDevice.png"), NULL);
 
 	if (engine.fullScreen)
-		screen = SDL_SetVideoMode(800, 600, 0, SDL_DOUBLEBUF|SDL_HWPALETTE|SDL_FULLSCREEN);
+		screen = SDL_SetVideoMode(screenWidth, screenHeight, 0, SDL_DOUBLEBUF|SDL_HWPALETTE|SDL_FULLSCREEN);
 	else
-		screen = SDL_SetVideoMode(800, 600, 0, SDL_DOUBLEBUF|SDL_HWPALETTE);
+		screen = SDL_SetVideoMode(screenWidth, screenHeight, 0, SDL_DOUBLEBUF|SDL_HWPALETTE);
 
 	if (screen == NULL) {
-		printf("Couldn't set 800x600x16 video mode: %s\n", SDL_GetError());
+		printf("Couldn't set %ix%ix16 video mode: %s\n", screenWidth, screenHeight, SDL_GetError());
 		exit(1);
 	}
 
diff --git a/code/intermission.cpp b/code/intermission.cpp
index e9322f9..ade8bff 100644
--- a/code/intermission.cpp
+++ b/code/intermission.cpp
@@ -34,8 +34,8 @@ static void doCursor()
 {
 	getPlayerInput();
 
-	limitInt(&engine.cursor_x, 10, 790);
-	limitInt(&engine.cursor_y, 10, 590);
+	limitInt(&engine.cursor_x, 10, screen->w - 10);
+	limitInt(&engine.cursor_y, 10, screen->h - 10);
 	blit(shape[0], engine.cursor_x, engine.cursor_y);
 }
 
@@ -442,7 +442,7 @@ static void showOptions(SDL_Surface *optionsSurface)
 				#if LINUX
 				SDL_WM_ToggleFullScreen(screen);
 				#else
-				screen = SDL_SetVideoMode(800, 600, 0, SDL_DOUBLEBUF|SDL_HWPALETTE|SDL_FULLSCREEN);
+				screen = SDL_SetVideoMode(screen->w, screen->h, 0, SDL_DOUBLEBUF|SDL_HWPALETTE|SDL_FULLSCREEN);
 				drawBackground();
 				flushBuffer();
 				#endif
@@ -457,7 +457,7 @@ static void showOptions(SDL_Surface *optionsSurface)
 				#if LINUX
 				SDL_WM_ToggleFullScreen(screen);
 				#else
-				screen = SDL_SetVideoMode(800, 600, 0, SDL_DOUBLEBUF|SDL_HWPALETTE);
+				screen = SDL_SetVideoMode(screen->w, screen->h, 0, SDL_DOUBLEBUF|SDL_HWPALETTE);
 				drawBackground();
 				flushBuffer();
 				#endif
@@ -503,7 +503,8 @@ int galaxyMap()
 
 	char string[25];
 
-	engine.cursor_x = engine.cursor_y = 500;
+	engine.cursor_x = (int)(screen->w / 2);
+	engine.cursor_y = (int)(screen->h / 2);
 	shape[0] = loadImage("gfx/cursor.png");
 
 	// Icons 1 - 29
@@ -631,9 +632,9 @@ int galaxyMap()
 
 		r.x = 0;
 		r.y = 0;
-		r.h = 600;
+		r.h = screen->h;
 		r.w = 1;
-		for (int i = 40 ; i < 800 ; i+= 40)
+		for (int i = 40 ; i < screen->w ; i+= 40)
 		{
 			r.x = i;
 			SDL_FillRect(screen, &r, darkerBlue);
@@ -642,8 +643,8 @@ int galaxyMap()
 		r.x = 0;
 		r.y = 0;
 		r.h = 1;
-		r.w = 800;
-		for (int i = 40 ; i < 600 ; i+= 40)
+		r.w = screen->w;
+		for (int i = 40 ; i < screen->h ; i+= 40)
 		{
 			r.y = i;
 			SDL_FillRect(screen, &r, darkerBlue);
diff --git a/code/misc.cpp b/code/misc.cpp
index 219ca54..f0e4ac5 100644
--- a/code/misc.cpp
+++ b/code/misc.cpp
@@ -107,28 +107,31 @@ static void doTargetArrow()
 	int distX = (int)(enemy[engine.targetIndex].x - player.x);
 	int distY = (int)(enemy[engine.targetIndex].y - player.y);
 
-	if (distY < -300)
+	// TODO: This is not very good. It assumes the player is always at (400,300),
+	// which is not always true, resulting in the arrows sometimes not appearing when
+	// the enemy is not visible and sometimes appearing when the enemy is visible.
+	if (distY < (int)(-screen->h / 2))
 		engine.targetArrow = 36;
 
-	if (distY > 300)
+	if (distY > (int)(screen->h / 2))
 		engine.targetArrow = 40;
 
-	if (distX < -400)
+	if (distX < (int)(-screen->w / 2))
 		engine.targetArrow = 42;
 
-	if (distX > 400)
+	if (distX > (int)(screen->w / 2))
 		engine.targetArrow = 38;
 
-	if ((distY < -300) && (distX > 400))
+	if ((distY < (int)(-screen->h / 2)) && (distX > (int)(screen->w / 2)))
 		engine.targetArrow = 37;
 
-	if ((distY > 300) && (distX > 400))
+	if ((distY > (int)(screen->h / 2)) && (distX > (int)(screen->w / 2)))
 		engine.targetArrow = 39;
 
-	if ((distY > 300) && (distX < -400))
+	if ((distY > (int)(screen->h / 2)) && (distX < (int)(-screen->w / 2)))
 		engine.targetArrow = 41;
 
-	if ((distY < -300) && (distX < -400))
+	if ((distY < (int)(-screen->h / 2)) && (distX < (int)(-screen->w / 2)))
 		engine.targetArrow = 43;
 
 	if (engine.targetArrow != -1)
diff --git a/code/missions.cpp b/code/missions.cpp
index 6b92779..b0ef198 100644
--- a/code/missions.cpp
+++ b/code/missions.cpp
@@ -672,14 +672,14 @@ bool missionFailed()
 
 static void drawBriefScreen()
 {
-	SDL_Rect r = {0, 0, 800, 2};
+	SDL_Rect r = {0, 0, screen->w, 2};
 
-	for (int i = 0 ; i < 120 ; i++)
+	for (int i = 0 ; i < (int)(screen->h / 4) - 30 ; i++)
 	{
-		r.y = (i * 2) + 60;
+		r.y = (i * 2) + 62; // Not a typo; a black gap is left in the middle if it's 60.
+		SDL_FillRect(screen, &r, SDL_MapRGB(screen->format, 0, i, 0));
+		r.y = (screen->h - (i * 2) - 60);
 		SDL_FillRect(screen, &r, SDL_MapRGB(screen->format, 0, i, 0));
-		r.y = (300 + (i * 2));
-		SDL_FillRect(screen, &r, SDL_MapRGB(screen->format, 0, (120 - i), 0));
 	}
 
 	blevelRect(140, 70, 500, 20, 0x00, 0x77, 0x00);
diff --git a/code/player.cpp b/code/player.cpp
index 7ef3c8f..2a390dd 100644
--- a/code/player.cpp
+++ b/code/player.cpp
@@ -28,8 +28,8 @@ Initialises the player for a new game.
 void initPlayer()
 {
 	player.active = true;
-	player.x = 200;
-	player.y = 200;
+	player.x = (int)(screen->w / 2);
+	player.y = (int)(screen->h / 2);
 	player.speed = 2;
 	player.maxShield = (25 * currentGame.shieldUnits);
 	player.systemPower = player.maxShield;
@@ -217,8 +217,8 @@ void doPlayer()
 
 			if (engine.done == 0)
 			{
-				limitFloat(&player.x, 100, 700);
-				limitFloat(&player.y, 100, 500);
+				limitFloat(&player.x, viewBorder, screen->w - viewBorder);
+				limitFloat(&player.y, viewBorder, screen->h - viewBorder);
 			}
 
 			if (player.shield > engine.lowShield)
@@ -362,9 +362,9 @@ void leaveSector()
 		{
 			player.x += engine.ssx;
 			engine.ssx -= 1;
-			if (player.y > 300)
+			if (player.y > screen->h)
 				player.y--;
-			if (player.y < 300)
+			if (player.y < screen->h)
 				player.y++;
 		}
 
@@ -380,7 +380,7 @@ void leaveSector()
 		player.face = 0;
 		player.x += 12;
 		engine.ssx -= 0.2;
-		if (player.x > 1600)
+		if (player.x > (2 * screen->w))
 			engine.done = 1;
 	}
 }
diff --git a/code/script.cpp b/code/script.cpp
index 58e577b..1d49b88 100644
--- a/code/script.cpp
+++ b/code/script.cpp
@@ -272,14 +272,14 @@ void doCutscene(int scene)
 				enemy[i].y += enemy[i].dy;
 				enemy[i].x += engine.ssx;
 				blit(enemy[i].image[0], (int)enemy[i].x, (int)enemy[i].y);
-				if (enemy[i].x > 850)
+				if (enemy[i].x > (screen->w + 50))
 				{
 					enemy[i].x = -50;
-					enemy[i].y = rand() % 560;
+					enemy[i].y = rand() % (screen->h - 40);
 				}
 				if (enemy[i].y < -50)
-					enemy[i].y = 650;
-				if (enemy[i].y > 650)
+					enemy[i].y = (screen->h + 50);
+				if (enemy[i].y > (screen->h + 50))
 					enemy[i].y = -50;
 			}
 		}
@@ -308,7 +308,7 @@ void doCutscene(int scene)
 		}
 
 		if ((showMessage) && (messageBox != NULL))
-			blit(messageBox, (800 - messageBox->w) / 2, 500);
+			blit(messageBox, (screen->w - messageBox->w) / 2, screen->h - 100);
 
 		delayFrame();
 
diff --git a/code/title.cpp b/code/title.cpp
index 9a170da..fa7bce3 100644
--- a/code/title.cpp
+++ b/code/title.cpp
@@ -171,11 +171,11 @@ int doTitle()
 	prlogo = loadImage("gfx/prlogo.png");
 	sflogo = loadImage("gfx/sflogo.png");
 
-	int prx = ((800 - prlogo->w) / 2);
-	int pry = ((600 - prlogo->h) / 2);
+	int prx = ((screen->w - prlogo->w) / 2);
+	int pry = ((screen->h - prlogo->h) / 2);
 
-	int sfx = ((800 - sflogo->w) / 2);
-	int sfy = ((600 - sflogo->h) / 2);
+	int sfx = ((screen->w - sflogo->w) / 2);
+	int sfy = ((screen->h - sflogo->h) / 2);
 
 	textSurface(0, "PRESENTS", -1, 300, FONT_WHITE);
 	textSurface(1, "AN SDL GAME", -1, 300, FONT_WHITE);
@@ -205,8 +205,8 @@ int doTitle()
 			enemy[i] = defEnemy[CD_TRANSPORTSHIP];
 		if ((rand() % 5) == 0)
 			enemy[i] = defEnemy[CD_MINER];
-		enemy[i].x = rand() % 800;
-		enemy[i].y = rand() % 560;
+		enemy[i].x = rand() % screen->w;
+		enemy[i].y = rand() % (screen->h - 40);
 		enemy[i].dx = 1 + rand() % 3;
 		enemy[i].face = 0;
 	}
@@ -258,7 +258,7 @@ int doTitle()
 			if (enemy[i].x > 830)
 			{
 				enemy[i].x = -40;
-				enemy[i].y = rand() % 580;
+				enemy[i].y = rand() % (screen->h - 20);
 				enemy[i].dx = 1 + rand() % 3;
 			}
 		}
@@ -414,9 +414,9 @@ int doTitle()
 							SDL_WM_ToggleFullScreen(screen);
 							#else
 							if (engine.fullScreen)
-								screen = SDL_SetVideoMode(800, 600, 0, SDL_DOUBLEBUF|SDL_HWPALETTE|SDL_FULLSCREEN);
+								screen = SDL_SetVideoMode(screen->w, screen->h, 0, SDL_DOUBLEBUF|SDL_HWPALETTE|SDL_FULLSCREEN);
 							else
-								screen = SDL_SetVideoMode(800, 600, 0, SDL_DOUBLEBUF|SDL_HWPALETTE);
+								screen = SDL_SetVideoMode(screen->w, screen->h, 0, SDL_DOUBLEBUF|SDL_HWPALETTE);
 
 							drawBackground();
 							flushBuffer();
@@ -491,7 +491,7 @@ void showStory()
 {
 	freeGraphics();
 
-	int y = 620;
+	int y = screen->h + 20;
 
 	FILE *fp;
 
@@ -540,7 +540,7 @@ void showStory()
 		if ((engine.keyState[SDLK_LCTRL]) || (engine.keyState[SDLK_RCTRL]) || (engine.keyState[SDLK_SPACE]))
 			break;
 
-		if (textShape[8].y > 450)
+		if (textShape[8].y > (int)(screen->h / 2) + 150)
 		{
 			for (int i = 0 ; i < 9 ; i++)
 			{
@@ -585,8 +585,8 @@ void gameover()
 		Mix_PlayMusic(engine.music, 1);
 	}
 
-	int x = (800 - gameover->w) / 2;
-	int y = (600 - gameover->h) / 2;
+	int x = (screen->w - gameover->w) / 2;
+	int y = (screen->h - gameover->h) / 2;
 
 	updateScreen();
 
@@ -603,8 +603,8 @@ void gameover()
 		updateScreen();
 
 		unBuffer();
-		x = ((800 - gameover->w) / 2) - rrand(-2, 2);
-		y = ((600 - gameover->h) / 2)  - rrand(-2, 2);
+		x = ((screen->w - gameover->w) / 2) - rrand(-2, 2);
+		y = ((screen->h - gameover->h) / 2)  - rrand(-2, 2);
 		blit(gameover, x,  y);
 
 		delayFrame();
@@ -632,7 +632,7 @@ void doCredits()
 	int lastCredit = 0;
 
 	int yPos = 0;
-	int yPos2 = 600;
+	int yPos2 = screen->h;
 	char text[255];
 
 	textObject *credit;
@@ -665,7 +665,7 @@ void doCredits()
 	{
 		fscanf(fp, "%d %[^\n]%*c", &yPos, text);
 		credit[i].image = textSurface(text, FONT_WHITE);
-		credit[i].x = (800 - credit[i].image->w) / 2;
+		credit[i].x = (screen->w - credit[i].image->w) / 2;
 		yPos2 += yPos;
 		credit[i].y = yPos2;
 	}
@@ -706,11 +706,11 @@ void doCredits()
 
 		for (int i = 0 ; i < numberOfCredits ; i++)
 		{
-			if ((credit[i].y > -10) && (credit[i].y < 610))
+			if ((credit[i].y > -10) && (credit[i].y < (screen->h + 10)))
 				blit(credit[i].image, (int)credit[i].x, (int)credit[i].y);
-			if (speed > 0 && credit[lastCredit].y > 400)
+			if (speed > 0 && credit[lastCredit].y > ((int)(screen->h / 2) + 100))
 				credit[i].y -= speed;
-			else if(speed < 0 && credit[0].y < 600)
+			else if(speed < 0 && credit[0].y < screen->h)
 				credit[i].y -= speed;
 		}