diff --git a/animationfunctions.ino b/animationfunctions.ino
index d92a0f3..436ac7a 100644
--- a/animationfunctions.ino
+++ b/animationfunctions.ino
@@ -330,7 +330,6 @@ int randomtetris(bool init){
       }
     }
     else{
-      uint8_t tempscreen[HEIGHT+3][WIDTH] = {0};
       uint8_t moveX = WIDTH-1;
       uint8_t moveY = HEIGHT+2;
       // moving blocks exists -> move them one pixel down
@@ -338,7 +337,6 @@ int randomtetris(bool init){
       for(int c = WIDTH-1; c >= 0; c--){
         for(int r = HEIGHT+1; r >= 0; r--){
           if((screen[r][c] != 0) && tomove[screen[r][c]]){
-            tempscreen[r+1][c] = screen[r][c];
             screen[r+1][c] = screen[r][c];
             screen[r][c] = 0;
             // save top left corner of block
diff --git a/ledmatrix.cpp b/ledmatrix.cpp
index da5919b..28935cf 100644
--- a/ledmatrix.cpp
+++ b/ledmatrix.cpp
@@ -135,7 +135,7 @@ void LEDMatrix::setMinIndicator(uint8_t pattern, uint32_t color)
 void LEDMatrix::gridAddPixel(uint8_t x, uint8_t y, uint32_t color)
 {
   // limit ranges of x and y
-  if(x >= 0 && x < WIDTH && y >= 0 && y < HEIGHT){
+  if(x < WIDTH && y < HEIGHT){
     targetgrid[y][x] = color;
   }
   else{
diff --git a/ntp_client_plus.cpp b/ntp_client_plus.cpp
index 9de9488..5cdd252 100644
--- a/ntp_client_plus.cpp
+++ b/ntp_client_plus.cpp
@@ -250,7 +250,7 @@ void NTPClientPlus::calcDate()
 
     // calc how many leap days since 1.Jan 1900
     int leapDays = 0;
-    for (int i = 1900; i < this->_dateYear; i++)
+    for (unsigned int i = 1900; i < this->_dateYear; i++)
     {
         // check if leap year
         if (this->isLeapYear(i))
@@ -278,7 +278,7 @@ void NTPClientPlus::calcDate()
     this->_dateDay = 0;
 
     // calc day of month
-    for (int i = 0; i < this->_dateMonth; i++)
+    for (unsigned int i = 0; i < this->_dateMonth; i++)
     {
         this->_dateDay = this->_dateDay + daysInMonth[i];
     }
@@ -289,7 +289,7 @@ void NTPClientPlus::calcDate()
     // 1. Januar 1900 was a monday
     this->_dayOfWeek = 1;
 
-    for (int i = 0; i < days1900; i++)
+    for (unsigned long i = 0; i < days1900; i++)
     {
 
         if (this->_dayOfWeek < 7)
@@ -335,7 +335,7 @@ unsigned int NTPClientPlus::getYear()
     unsigned int days = 0;
     unsigned int days1900 = 0;
 
-    int for_i = 0;
+    unsigned long for_i = 0;
     bool leapYear = LOW;
 
     days1900 = sec1900 / this->secondperday;
diff --git a/pong.cpp b/pong.cpp
index c30e7e3..49cceff 100644
--- a/pong.cpp
+++ b/pong.cpp
@@ -56,7 +56,7 @@ void Pong::loopCycle(){
  * @param playerid id of player {0, 1}
  */
 void Pong::ctrlUp(uint8_t playerid){
-    if (millis() > _lastButtonClick + DEBOUNCE_TIME) {
+    if (millis() > _lastButtonClick + DEBOUNCE_TIME_PONG) {
         _playerMovement[playerid] = PADDLE_MOVE_DOWN; // need to swap direction as field is rotated 180deg
         _lastButtonClick = millis();
     }
@@ -68,7 +68,7 @@ void Pong::ctrlUp(uint8_t playerid){
  * @param playerid id of player {0, 1}
  */
 void Pong::ctrlDown(uint8_t playerid){
-    if (millis() > _lastButtonClick + DEBOUNCE_TIME) {
+    if (millis() > _lastButtonClick + DEBOUNCE_TIME_PONG) {
         _playerMovement[playerid] = PADDLE_MOVE_UP; // need to swap direction as field is rotated 180deg
         _lastButtonClick = millis();
     }
@@ -80,7 +80,7 @@ void Pong::ctrlDown(uint8_t playerid){
  * @param playerid id of player {0, 1}
  */
 void Pong::ctrlNone(uint8_t playerid){
-    if (millis() > _lastButtonClick + DEBOUNCE_TIME) {
+    if (millis() > _lastButtonClick + DEBOUNCE_TIME_PONG) {
         _playerMovement[playerid] = PADDLE_MOVE_NONE;
         _lastButtonClick = millis();
     }
@@ -189,7 +189,7 @@ void Pong::endGame()
  */
 void Pong::updateGame()
 {
-    if ((millis() - _lastDrawUpdate) < GAME_DELAY) {
+    if ((millis() - _lastDrawUpdate) < GAME_DELAY_PONG) {
         return;
     }
     _lastDrawUpdate = millis();
@@ -273,7 +273,7 @@ void Pong::resetLEDs()
  */
 void Pong::toggleLed(uint8_t x, uint8_t y, uint8_t type)
 {
-    uint32_t color;
+    uint32_t color = LEDMatrix::Color24bit(0, 0, 0);
 
     switch(type) {
         case LED_TYPE_PADDLE:
diff --git a/pong.h b/pong.h
index e873e66..e5c226c 100644
--- a/pong.h
+++ b/pong.h
@@ -18,12 +18,12 @@
 #include "ledmatrix.h"
 #include "udplogger.h"
 
-#define DEBOUNCE_TIME 10  // in ms
+#define DEBOUNCE_TIME_PONG 10  // in ms
 
 #define X_MAX 11
 #define Y_MAX 11
 
-#define GAME_DELAY 80         // in ms
+#define GAME_DELAY_PONG 80         // in ms
 #define BALL_DELAY_MAX   350  // in ms
 #define BALL_DELAY_MIN    50  // in ms
 #define BALL_DELAY_STEP    5  // in ms
diff --git a/snake.cpp b/snake.cpp
index bffe225..c8cb119 100644
--- a/snake.cpp
+++ b/snake.cpp
@@ -56,7 +56,7 @@ void Snake::loopCycle()
  * 
  */
 void Snake::ctrlUp(){
-    if (millis() > _lastButtonClick + DEBOUNCE_TIME && _gameState == GAME_STATE_RUNNING) {
+    if (millis() > _lastButtonClick + DEBOUNCE_TIME_SNAKE && _gameState == GAME_STATE_RUNNING) {
         (*_logger).logString("Snake: UP");
         _userDirection = DIRECTION_DOWN; // need to swap direction as field is rotated 180deg
         _lastButtonClick = millis();
@@ -68,7 +68,7 @@ void Snake::ctrlUp(){
  * 
  */
 void Snake::ctrlDown(){
-    if (millis() > _lastButtonClick + DEBOUNCE_TIME && _gameState == GAME_STATE_RUNNING) {
+    if (millis() > _lastButtonClick + DEBOUNCE_TIME_SNAKE && _gameState == GAME_STATE_RUNNING) {
         (*_logger).logString("Snake: DOWN");
         _userDirection = DIRECTION_UP; // need to swap direction as field is rotated 180deg
         _lastButtonClick = millis();
@@ -80,7 +80,7 @@ void Snake::ctrlDown(){
  * 
  */
 void Snake::ctrlRight(){
-    if (millis() > _lastButtonClick + DEBOUNCE_TIME && _gameState == GAME_STATE_RUNNING) {
+    if (millis() > _lastButtonClick + DEBOUNCE_TIME_SNAKE && _gameState == GAME_STATE_RUNNING) {
         (*_logger).logString("Snake: RIGHT");
         _userDirection = DIRECTION_LEFT; // need to swap direction as field is rotated 180deg
         _lastButtonClick = millis();
@@ -92,7 +92,7 @@ void Snake::ctrlRight(){
  * 
  */
 void Snake::ctrlLeft(){
-    if (millis() > _lastButtonClick + DEBOUNCE_TIME && _gameState == GAME_STATE_RUNNING) {
+    if (millis() > _lastButtonClick + DEBOUNCE_TIME_SNAKE && _gameState == GAME_STATE_RUNNING) {
         (*_logger).logString("Snake: LEFT");
         _userDirection = DIRECTION_RIGHT; // need to swap direction as field is rotated 180deg
         _lastButtonClick = millis();
@@ -138,9 +138,9 @@ void Snake::initGame()
  */
 void Snake::updateGame()
 {
-  if ((millis() - _lastDrawUpdate) > GAME_DELAY) {
+  if ((millis() - _lastDrawUpdate) > GAME_DELAY_SNAKE) {
     (*_logger).logString("Snake: update game");
-    toggleLed(_tail[_wormLength-1].x, _tail[_wormLength-1].y, LED_TYPE_OFF);
+    toggleLed(_tail[_wormLength-1].x, _tail[_wormLength-1].y, LED_TYPE_EMPTY);
     switch(_userDirection) {
       case DIRECTION_RIGHT:
         if (_head.x > 0) {
@@ -198,14 +198,14 @@ void Snake::endGame()
  */
 void Snake::updateTail()
 {
-  for(int i=_wormLength-1; i>0; i--) {
+  for(unsigned int i=_wormLength-1; i>0; i--) {
     _tail[i].x = _tail[i-1].x;
     _tail[i].y = _tail[i-1].y;
   }
   _tail[0].x = _head.x;
   _tail[0].y = _head.y;
 
-  for(int i=0; i<_wormLength; i++) {
+  for(unsigned int i=0; i<_wormLength; i++) {
     if (_tail[i].x > -1) {
       toggleLed(_tail[i].x, _tail[i].y, LED_TYPE_SNAKE);
     }
@@ -223,7 +223,7 @@ void Snake::updateFood()
     found = true;
     _food.x = random(0, X_MAX);
     _food.y = random(0, Y_MAX);
-    for(int i=0; i<_wormLength; i++) {
+    for(unsigned int i=0; i<_wormLength; i++) {
       if (_tail[i].x == _food.x && _tail[i].y == _food.y) {
          found = false;
       }
@@ -246,7 +246,7 @@ bool Snake::isCollision()
   if (_head.y < 0 || _head.y >= Y_MAX) {
     return true;
   }
-  for(int i=1; i<_wormLength; i++) {
+  for(unsigned int i=1; i<_wormLength; i++) {
     if (_tail[i].x == _head.x && _tail[i].y == _head.y) {
        return true;
     }
@@ -263,13 +263,13 @@ bool Snake::isCollision()
  */
 void Snake::toggleLed(uint8_t x, uint8_t y, uint8_t type)
 {
-  uint32_t color;
+  uint32_t color = LEDMatrix::Color24bit(0, 0, 0);
 
   switch(type) {
     case LED_TYPE_SNAKE:
       color = LEDMatrix::Color24bit(0, 100, 100);
       break;
-    case LED_TYPE_OFF:
+    case LED_TYPE_EMPTY:
       color = LEDMatrix::Color24bit(0, 0, 0);
       break;
     case LED_TYPE_FOOD:
diff --git a/snake.h b/snake.h
index f5d6abf..f4619cb 100644
--- a/snake.h
+++ b/snake.h
@@ -17,15 +17,15 @@
 #include "ledmatrix.h"
 #include "udplogger.h"
 
-#define DEBOUNCE_TIME 300   // in ms
+#define DEBOUNCE_TIME_SNAKE 300   // in ms
 
 #define X_MAX 11
 #define Y_MAX 11
 
-#define GAME_DELAY 400      // in ms
+#define GAME_DELAY_SNAKE 400      // in ms
 
 #define LED_TYPE_SNAKE 1
-#define LED_TYPE_OFF   2
+#define LED_TYPE_EMPTY 2
 #define LED_TYPE_FOOD  3
 #define LED_TYPE_BLOOD 4
 
diff --git a/tetris.cpp b/tetris.cpp
index b605082..09fe84a 100644
--- a/tetris.cpp
+++ b/tetris.cpp
@@ -45,8 +45,8 @@ void Tetris::loopCycle(){
             if (_activeBrick.enabled) {
                 // move faster down when allow drop
                 if (_allowdrop) {
-                    if (millis() > _droptime + 50) {
-                        _droptime = millis();
+                    if (millis() > _dropTime + 50) {
+                        _dropTime = millis();
                         shiftActiveBrick(DIR_DOWN);
                         printField();
                     }
@@ -77,10 +77,10 @@ void Tetris::loopCycle(){
                 _tetrisGameOver = false;
                 (*_logger).logString("Tetris: end");
                 everythingRed();
-                _tetrisshowscore = millis();
+                _tetrisshowscoreTime = millis();
             }
 
-            if (millis() > (_tetrisshowscore + RED_END_TIME)) {
+            if (millis() > (_tetrisshowscoreTime + RED_END_TIME)) {
                 resetLEDs();
                 _score = _nbRowsTotal;
                 showscore();
@@ -95,7 +95,7 @@ void Tetris::loopCycle(){
  * 
  */
 void Tetris::ctrlStart() {
-    if (millis() > _lastButtonClick + DEBOUNCE_TIME)
+    if (millis() > _lastButtonClick + DEBOUNCE_TIME_TETRIS)
     {
         _lastButtonClick = millis();
         _gameStatet = GAME_STATE_INITt;
@@ -107,7 +107,7 @@ void Tetris::ctrlStart() {
  * 
  */
 void Tetris::ctrlPlayPause() {
-    if (millis() > _lastButtonClick + DEBOUNCE_TIME)
+    if (millis() > _lastButtonClick + DEBOUNCE_TIME_TETRIS)
     {
         _lastButtonClick = millis();
         if (_gameStatet == GAME_STATE_PAUSEDt) {
@@ -128,7 +128,7 @@ void Tetris::ctrlPlayPause() {
  * 
  */
 void Tetris::ctrlRight() {
-    if (millis() > _lastButtonClick + DEBOUNCE_TIME && _gameStatet == GAME_STATE_RUNNINGt)
+    if (millis() > _lastButtonClick + DEBOUNCE_TIME_TETRIS && _gameStatet == GAME_STATE_RUNNINGt)
     {
         _lastButtonClick = millis();
         shiftActiveBrick(DIR_RIGHT);
@@ -141,7 +141,7 @@ void Tetris::ctrlRight() {
  * 
  */
 void Tetris::ctrlLeft() {
-    if (millis() > _lastButtonClick + DEBOUNCE_TIME && _gameStatet == GAME_STATE_RUNNINGt)
+    if (millis() > _lastButtonClick + DEBOUNCE_TIME_TETRIS && _gameStatet == GAME_STATE_RUNNINGt)
     {
         _lastButtonClick = millis();
         shiftActiveBrick(DIR_LEFT);
@@ -154,7 +154,7 @@ void Tetris::ctrlLeft() {
  * 
  */
 void Tetris::ctrlUp() {
-    if (millis() > _lastButtonClick + DEBOUNCE_TIME && _gameStatet == GAME_STATE_RUNNINGt)
+    if (millis() > _lastButtonClick + DEBOUNCE_TIME_TETRIS && _gameStatet == GAME_STATE_RUNNINGt)
     {
         _lastButtonClick = millis();
         rotateActiveBrick();
@@ -168,7 +168,7 @@ void Tetris::ctrlUp() {
  */
 void Tetris::ctrlDown() {
     // longer debounce time, to prevent immediate drop
-    if (millis() > _lastButtonClickr + DEBOUNCE_TIME*5 && _gameStatet == GAME_STATE_RUNNINGt)
+    if (millis() > _lastButtonClickr + DEBOUNCE_TIME_TETRIS*5 && _gameStatet == GAME_STATE_RUNNINGt)
     {
         _allowdrop = true;
         _lastButtonClickr = millis();
@@ -178,9 +178,10 @@ void Tetris::ctrlDown() {
 /**
  * @brief Set game speed
  * 
- * @param i new speed value
+ * @param i new speed value (0 - 15)
  */
-void Tetris::setSpeed(int32_t i) {
+void Tetris::setSpeed(uint8_t i) {
+    if(i > 15) i = 15;
     (*_logger).logString("setSpeed: " + String(i));
     _speedtetris = -10 * i + 150;
 }
@@ -321,12 +322,11 @@ boolean Tetris::checkFieldCollision(struct Brick * brick) {
 boolean Tetris::checkSidesCollision(struct Brick * brick) {
     //Check vertical collision with sides of field
     uint8_t bx, by;
-    uint8_t fx, fy;
+    int8_t fx;
     for (by = 0; by < MAX_BRICK_SIZE; by++) {
         for (bx = 0; bx < MAX_BRICK_SIZE; bx++) {
             if ( (*brick).pix[bx][by] == 1) {
                 fx = (*brick).xpos + bx;//Determine actual position in the field of the current pix of the brick
-                fy = (*brick).ypos + by;
                 if (fx < 0 || fx >= WIDTH) {
                     return true;
                 }
@@ -450,7 +450,7 @@ void Tetris::shiftActiveBrick(int dir) {
  */
 void Tetris::addActiveBrickToField() {
     uint8_t bx, by;
-    uint8_t fx, fy;
+    int8_t fx, fy;
     for (by = 0; by < MAX_BRICK_SIZE; by++) {
         for (bx = 0; bx < MAX_BRICK_SIZE; bx++) {
             fx = _activeBrick.xpos + bx;
diff --git a/tetris.h b/tetris.h
index c06cef5..e5b372f 100644
--- a/tetris.h
+++ b/tetris.h
@@ -17,7 +17,7 @@
 #include "ledmatrix.h"
 #include "udplogger.h"
 
-#define DEBOUNCE_TIME 100
+#define DEBOUNCE_TIME_TETRIS 100
 #define RED_END_TIME 1500
 #define GAME_STATE_RUNNINGt 1
 #define GAME_STATE_ENDt     2
@@ -90,7 +90,7 @@ class Tetris{
         void ctrlLeft();
         void ctrlUp();
         void ctrlDown();
-        void setSpeed(int32_t i);
+        void setSpeed(uint8_t i);
 
         void loopCycle();
 
@@ -119,21 +119,20 @@ class Tetris{
         Brick _activeBrick;
         Field _field;
 
-        long _lastButtonClick = 0;
-        long _lastButtonClickr = 0;
+        unsigned long _lastButtonClick = 0;
+        unsigned long _lastButtonClickr = 0;
         int _score = 0;
         int _gameStatet = GAME_STATE_INITt;
-        uint16_t _brickSpeed;
+        unsigned int _brickSpeed;
         unsigned long _nbRowsThisLevel;
         unsigned long _nbRowsTotal;
 
         bool _tetrisGameOver;
 
         unsigned long _prevUpdateTime = 0;
-
-        long _tetrisshowscore;
-        long _droptime = 0;
-        int _speedtetris = 80;
+        unsigned long _tetrisshowscoreTime = 0;
+        unsigned long _dropTime = 0;
+        unsigned int _speedtetris = 80;
         bool _allowdrop;
         
         // color library
diff --git a/udplogger.h b/udplogger.h
index 8ec9c3d..c26fa49 100644
--- a/udplogger.h
+++ b/udplogger.h
@@ -31,7 +31,7 @@ class UDPLogger{
         int _port;
         WiFiUDP _Udp;
         char _packetBuffer[100];
-        long _lastSend;
+        unsigned long _lastSend;
 };
 
 #endif
\ No newline at end of file
diff --git a/wordclock_esp8266.ino b/wordclock_esp8266.ino
index a2fc0c2..00472e9 100644
--- a/wordclock_esp8266.ino
+++ b/wordclock_esp8266.ino
@@ -998,7 +998,6 @@ void handleCommand() {
  */
 String split(String s, char parser, int index) {
   String rs="";
-  int parserIndex = index;
   int parserCnt=0;
   int rFromIndex=0, rToIndex=-1;
   while (index >= parserCnt) {
diff --git a/wordclockfunctions.ino b/wordclockfunctions.ino
index 829ddab..ecbdc6e 100644
--- a/wordclockfunctions.ino
+++ b/wordclockfunctions.ino
@@ -42,11 +42,9 @@ void drawMinuteIndicator(uint8_t minutes, uint32_t color){
  * @return int: 0 if successful, -1 if sentence not possible to display
  */
 int showStringOnClock(String message, uint32_t color){
-    int messageStart = 0;
     String word = "";
     int lastLetterClock = 0;
     int positionOfWord  = 0;
-    int nextSpace = 0;
     int index = 0;
 
     // add space on the end of message for splitting
@@ -66,7 +64,7 @@ int showStringOnClock(String message, uint32_t color){
         
         if(positionOfWord >= 0){
           // word found on clock -> enable leds in targetgrid
-          for(int i = 0; i < word.length(); i++){
+          for(unsigned int i = 0; i < word.length(); i++){
             int x = (positionOfWord + i)%WIDTH;
             int y = (positionOfWord + i)/WIDTH;
             ledmatrix.gridAddPixel(x, y, color);
@@ -79,7 +77,6 @@ int showStringOnClock(String message, uint32_t color){
           logger.logString("word is not possible to show on clock: " + String(word));
           return -1;
         }
-        //logger.logString(String(nextSpace) + " - " + String());
       }else{
         // end - no more word in message
         break;
diff --git a/wordclockfunctions.ino_english b/wordclockfunctions.ino_english
index f76c3a8..0153b68 100644
--- a/wordclockfunctions.ino_english
+++ b/wordclockfunctions.ino_english
@@ -41,11 +41,9 @@ void drawMinuteIndicator(uint8_t minutes, uint32_t color) {
  * @return int: 0 if successful, -1 if sentence not possible to display
  */
 int showStringOnClock(String message, uint32_t color) {
-  int messageStart = 0;
   String word = "";
   int lastLetterClock = 0;
   int positionOfWord = 0;
-  int nextSpace = 0;
   int index = 0;
 
   // add space on the end of message for splitting
@@ -65,7 +63,7 @@ int showStringOnClock(String message, uint32_t color) {
 
       if (positionOfWord >= 0) {
         // word found on clock -> enable leds in targetgrid
-        for (int i = 0; i < word.length(); i++) {
+        for (unsigned int i = 0; i < word.length(); i++) {
           int x = (positionOfWord + i) % WIDTH;
           int y = (positionOfWord + i) / WIDTH;
           ledmatrix.gridAddPixel(x, y, color);
@@ -77,7 +75,6 @@ int showStringOnClock(String message, uint32_t color) {
         logger.logString("word is not possible to show on clock: " + String(word));
         return -1;
       }
-      //logger.logString(String(nextSpace) + " - " + String());
     } else {
       // end - no more word in message
       break;
diff --git a/wordclockfunctions.ino_italian b/wordclockfunctions.ino_italian
index f3b2a56..a1f0f47 100644
--- a/wordclockfunctions.ino_italian
+++ b/wordclockfunctions.ino_italian
@@ -42,11 +42,9 @@ void drawMinuteIndicator(uint8_t minutes, uint32_t color){
  * @return int: 0 if successful, -1 if sentence not possible to display
  */
 int showStringOnClock(String message, uint32_t color){
-    int messageStart = 0;
     String word = "";
     int lastLetterClock = 0;
     int positionOfWord  = 0;
-    int nextSpace = 0;
     int index = 0;
 
     // add space on the end of message for splitting
@@ -66,7 +64,7 @@ int showStringOnClock(String message, uint32_t color){
         
         if(positionOfWord >= 0){
           // word found on clock -> enable leds in targetgrid
-          for(int i = 0; i < word.length(); i++){
+          for(unsigned int i = 0; i < word.length(); i++){
             int x = (positionOfWord + i)%WIDTH;
             int y = (positionOfWord + i)/WIDTH;
             ledmatrix.gridAddPixel(x, y, color);
@@ -79,7 +77,6 @@ int showStringOnClock(String message, uint32_t color){
           logger.logString("word is not possible to show on clock: " + String(word));
           return -1;
         }
-        //logger.logString(String(nextSpace) + " - " + String());
       }else{
         // end - no more word in message
         break;