diff --git a/source/code/Libs/NFont.h b/source/code/Libs/NFont.h
index c8f5d4e..0d6d581 100644
--- a/source/code/Libs/NFont.h
+++ b/source/code/Libs/NFont.h
@@ -191,24 +191,24 @@ public:
 	void freeSurface();
 
 	// Drawing
-	SDL_Rect draw(int x, int y, const char* formatted_text, ...) const;
-	SDL_Rect drawCenter(int x, int y, const char* formatted_text, ...) const;
-	SDL_Rect drawRight(int x, int y, const char* formatted_text, ...) const;
-	SDL_Rect drawPos(int x, int y, NFont::AnimFn posFn, const char* text, ...) const;
-	SDL_Rect drawAll(int x, int y, NFont::AnimFn allFn, const char* text, ...) const;
+	SDL_Rect draw(int x, int y, const char* formatted_text, ...) const __attribute__ ((format (printf, 4, 5)));
+	SDL_Rect drawCenter(int x, int y, const char* formatted_text, ...) const __attribute__ ((format (printf, 4, 5)));
+	SDL_Rect drawRight(int x, int y, const char* formatted_text, ...) const __attribute__ ((format (printf, 4, 5)));
+	SDL_Rect drawPos(int x, int y, NFont::AnimFn posFn, const char* text, ...) const __attribute__ ((format (printf, 5, 6)));
+	SDL_Rect drawAll(int x, int y, NFont::AnimFn allFn, const char* text, ...) const __attribute__ ((format (printf, 5, 6)));
 
 	// Getters
 	SDL_Surface* getDest() const;
 	SDL_Surface* getSurface() const;
-	int getHeight(const char* formatted_text = NULL, ...) const;
-	int getWidth(const char* formatted_text, ...) const;
+	int getHeight(const char* formatted_text = NULL, ...) const __attribute__ ((format (printf, 2, 3)));
+	int getWidth(const char* formatted_text, ...) const __attribute__ ((format (printf, 2, 3)));
 	int getSpacing() const;
 	int getLineSpacing() const;
 	int getBaseline() const;
 	int getAscent(const char character) const;
-	int getAscent(const char* formatted_text = NULL, ...) const;
+	int getAscent(const char* formatted_text = NULL, ...) const __attribute__ ((format (printf, 2, 3)));
 	int getDescent(const char character) const;
-	int getDescent(const char* formatted_text = NULL, ...) const;
+	int getDescent(const char* formatted_text = NULL, ...) const __attribute__ ((format (printf, 2, 3)));
 	int getMaxWidth() const;
 
 	// Setters
diff --git a/source/code/MenuSystem.cpp b/source/code/MenuSystem.cpp
index e9ce9b5..0a61132 100644
--- a/source/code/MenuSystem.cpp
+++ b/source/code/MenuSystem.cpp
@@ -106,7 +106,7 @@ void Button::drawTo(SDL_Surface** surface) {
 		gfx->unmarked->PaintTo(*surface,x,y);
 	}
 	gfx->thefont.setDest(*surface);
-	gfx->thefont.drawCenter(x+gfx->xsize/2,y+gfx->ysize/2-gfx->thefont.getHeight(label.c_str())/2,label.c_str());
+	gfx->thefont.drawCenter(x+gfx->xsize/2,y+gfx->ysize/2-gfx->thefont.getHeight("%s", label.c_str())/2, "%s", label.c_str());
 }
 
 void Button::setPopOnRun(bool popOnRun) {
@@ -132,7 +132,7 @@ void Menu::drawSelf() {
 		(*it)->drawTo(&screen);
 	}
 	exit.drawTo(&screen);
-	standardButton.thefont.draw(50,50,title.c_str());
+	standardButton.thefont.draw(50, 50, "%s", title.c_str());
 	mouse->PaintTo(screen,mousex,mousey);
 }
 
diff --git a/source/code/ReadKeyboard.cpp b/source/code/ReadKeyboard.cpp
index 71b1837..a7860de 100644
--- a/source/code/ReadKeyboard.cpp
+++ b/source/code/ReadKeyboard.cpp
@@ -121,8 +121,6 @@ bool ReadKeyboard::ReadKey(SDLKey keyPressed) {
 		}
 		return false;
 	}
-	Uint8* keys;
-	keys = SDL_GetKeyState(nullptr);
 	if (keyPressed == SDLK_HOME) {
 		position=0;
 		return true;
diff --git a/source/code/main.cpp b/source/code/main.cpp
index 9322628..a9f5074 100644
--- a/source/code/main.cpp
+++ b/source/code/main.cpp
@@ -696,7 +696,7 @@ void DrawIMG(SDL_Surface* img, SDL_Surface* target, int x, int y, int w, int h, 
 
 void NFont_Write(SDL_Surface* target, int x, int y, const string& text) {
 	nf_standard_blue_font.setDest(target);
-	nf_standard_blue_font.draw(x, y, text.c_str());
+	nf_standard_blue_font.draw(x, y, "%s", text.c_str());
 	nf_standard_blue_font.setDest(screen);
 }
 
@@ -1252,7 +1252,7 @@ public:
 		if (puzzleMode&&(!bGameOver)) {
 			//We need to write nr. of moves left!
 			strHolder = "Moves left: " + itoa(MovesLeft);
-			nf_standard_blue_font.draw(5,5,strHolder.c_str());
+			nf_standard_blue_font.draw(5,5, "%s",strHolder.c_str());
 
 		}
 		if (puzzleMode && stageButtonStatus == SBpuzzleMode) {
@@ -1267,7 +1267,7 @@ public:
 			}
 			else {
 				strHolder = "Last puzzle";
-				nf_standard_blue_font.draw(5,5,strHolder.c_str());
+				nf_standard_blue_font.draw(5,5, "%s",strHolder.c_str());
 			}
 		}
 		if (stageClear && stageButtonStatus == SBstageClear) {
@@ -1282,7 +1282,7 @@ public:
 			}
 			else {
 				strHolder = "Last stage";
-				nf_standard_blue_font.draw(5,5,strHolder.c_str());
+				nf_standard_blue_font.draw(5,5, "%s",strHolder.c_str());
 			}
 		}
 
@@ -1290,7 +1290,7 @@ public:
 		if (AI_Enabled&&(!bGameOver)) {
 			strHolder = "AI_status: " + itoa(AIstatus)+ ", "+ itoa(AIlineToClear);
 			//NFont_Write(sBoard,   5, 5, strHolder.c_str());
-			nf_standard_blue_font.draw(5,5,strHolder.c_str());
+			nf_standard_blue_font.draw(5,5, "%s",strHolder.c_str());
 		}
 #endif
 		if (!bGameOver) {
@@ -1419,7 +1419,7 @@ bool OpenDialogbox(int x, int y, char* name) {
 		strHolder.erase((int)rk.CharsBeforeCursor());
 
 		if (((SDL_GetTicks()/600)%2)==1) {
-			NFont_Write(screen, x+40+nf_standard_blue_font.getWidth( strHolder.c_str()),y+76,"|");
+			NFont_Write(screen, x+40+nf_standard_blue_font.getWidth( "%s", strHolder.c_str()),y+76,"|");
 		}
 
 		SDL_Event event;
@@ -1468,10 +1468,10 @@ void DrawHighscores(int x, int y, bool endless) {
 	MakeBackground(xsize,ysize);
 	DrawIMG(background,screen,0,0);
 	if (endless) {
-		nf_standard_blue_font.draw(x+100,y+100,_("Endless:") );
+		nf_standard_blue_font.draw(x+100,y+100, "%s",_("Endless:") );
 	}
 	else {
-		nf_standard_blue_font.draw(x+100,y+100,_("Time Trial:") );
+		nf_standard_blue_font.draw(x+100,y+100, "%s",_("Time Trial:") );
 	}
 	for (int i =0; i<10; i++) {
 		char playerScore[32];
@@ -1488,8 +1488,8 @@ void DrawHighscores(int x, int y, bool endless) {
 		else {
 			strcpy(playerName,theTopScoresTimeTrial.getScoreName(i));
 		}
-		nf_standard_blue_font.draw(x+420,y+150+i*35,playerScore);
-		nf_standard_blue_font.draw(x+60,y+150+i*35,playerName);
+		nf_standard_blue_font.draw(x+420,y+150+i*35, "%s",playerScore);
+		nf_standard_blue_font.draw(x+60,y+150+i*35, "%s",playerName);
 	}
 }
 
@@ -1589,7 +1589,7 @@ void OpenScoresDisplay() {
 
 		//Draw page number
 		string pageXofY = (boost::format(_("Page %1% of %2%") )%(page+1)%numberOfPages).str();
-		NFont_Write(screen, xsize/2-nf_standard_blue_font.getWidth( pageXofY.c_str())/2,ysize-60,pageXofY.c_str());
+		NFont_Write(screen, xsize/2-nf_standard_blue_font.getWidth( "%s", pageXofY.c_str())/2,ysize-60,pageXofY.c_str());
 
 		SDL_Delay(10);
 		SDL_Event event;
@@ -1776,7 +1776,7 @@ static void DrawBalls() {
 			int x = theTextManeger.textArray[i].getX()-12;
 			int y = theTextManeger.textArray[i].getY()-12;
 			DrawIMG(iChainBack,screen,x,y);
-			nf_standard_small_font.drawCenter(x+12,y+7,theTextManeger.textArray[i].getText());
+			nf_standard_small_font.drawCenter(x+12,y+7, "%s",theTextManeger.textArray[i].getText());
 		}
 	} //for
 }    //DrawBalls