diff --git a/js/game.js b/js/game.js
index e23f454..c420824 100644
--- a/js/game.js
+++ b/js/game.js
@@ -2,7 +2,7 @@
  * Game (Model + Controller)
  */
 function Game(Interface) {
-  var self = this;
+  let self = this;
 
   // get interface
   self.Interface = new Interface;
@@ -20,7 +20,7 @@ function Game(Interface) {
 /**
  * Restart game (reset)
  */
-Game.prototype.restart = function() {
+Game.prototype.restart = function () {
   this.Interface.setup();
   this.setup();
 };
@@ -28,8 +28,8 @@ Game.prototype.restart = function() {
 /**
  * Setup new game
  */
-Game.prototype.setup = function() {
-  var self = this;
+Game.prototype.setup = function () {
+  let self = this;
   self.player = {
     score: 0,
     zilch: 0
@@ -40,8 +40,8 @@ Game.prototype.setup = function() {
   };
   self.dices = []
 
-  for (var i = 0; i < 6; i++) {
-    var dice = {};
+  for (let i = 0; i < 6; i++) {
+    let dice = {};
     dice.value = this.random(6);
     dice.disabled = true;
     self.dices[i] = dice;
@@ -67,13 +67,13 @@ Game.prototype.setup = function() {
 
   if (self.cpuStarts) {
     self.Interface.disableRestart(true);
-    self.Interface.showMessage("CPU starts!", self.messageTime, function() {
-      setTimeout(function() {
+    self.Interface.showMessage("CPU starts!", self.messageTime, function () {
+      setTimeout(function () {
         self.rollDices();
       }, self.cpuSpeed);
     });
   } else {
-    self.Interface.showMessage("Player starts!", 0, function() {
+    self.Interface.showMessage("Player starts!", 0, function () {
       self.Interface.disableRestart(false);
       self.Interface.disableRollDices(false);
     });
@@ -85,15 +85,15 @@ Game.prototype.setup = function() {
 /**
  * Random helper for integer numbers
  */
-Game.prototype.random = function(int) {
+Game.prototype.random = function (int) {
   return Math.floor((Math.random() * int));
 };
 
 /**
  * Roll dices
  */
-Game.prototype.rollDices = function(all) {
-  var self = this;
+Game.prototype.rollDices = function (all) {
+  let self = this;
   self.Interface.clearMessage();
 
   if (self.newRound) {
@@ -102,10 +102,10 @@ Game.prototype.rollDices = function(all) {
     self.newRound = false;
   }
 
-  var rollCount = 0;
-  for (var i = 0; i < 6; i++) {
+  let rollCount = 0;
+  for (let i = 0; i < 6; i++) {
     self.dices[i] = self.dices[i] || {};
-    var dice = self.dices[i];
+    let dice = self.dices[i];
     if (all || !dice.disabled) {
       dice.value = this.random(6);
       if (all) {
@@ -122,11 +122,11 @@ Game.prototype.rollDices = function(all) {
   if (rollCount == 0) {
     self.rollDices(true);
   } else if (self.calculatePoints(true) == 0) {
-    self.Interface.animateDices(self.dices, self.animationTime, function() {
+    self.Interface.animateDices(self.dices, self.animationTime, function () {
       if (self.playing) {
         self.player.zilch++;
 
-        var history = {};
+        let history = {};
         history['player'] = 'Zilch';
         self.history.push(history);
         self.points = 0;
@@ -139,7 +139,7 @@ Game.prototype.rollDices = function(all) {
           }
 
 
-          var history = {};
+          let history = {};
           history['player'] = '-500';
           self.history.push(history);
           self.points = -500;
@@ -150,7 +150,7 @@ Game.prototype.rollDices = function(all) {
         self.Interface.setPoints(self.points);
         self.Interface.setPlayer(self.player);
 
-        self.Interface.showMessage("Zilch!", self.messageTime, function() {
+        self.Interface.showMessage("Zilch!", self.messageTime, function () {
           if (self.player.zilch > 2) {
             self.player.zilch = 0;
             self.Interface.setPlayer(self.player);
@@ -162,7 +162,7 @@ Game.prototype.rollDices = function(all) {
       } else {
         self.cpu.zilch++;
 
-        var history = {};
+        let history = {};
         history['cpu'] = 'Zilch';
         self.history.push(history);
         self.points = 0;
@@ -174,7 +174,7 @@ Game.prototype.rollDices = function(all) {
             self.cpu.score -= 500;
           }
 
-          var history = {};
+          let history = {};
           history['cpu'] = '-500';
           self.history.push(history);
           self.points = -500;
@@ -185,7 +185,7 @@ Game.prototype.rollDices = function(all) {
         self.Interface.setPoints(self.points);
         self.Interface.setCpu(self.cpu);
 
-        self.Interface.showMessage("Zilch!", self.messageTime, function() {
+        self.Interface.showMessage("Zilch!", self.messageTime, function () {
           if (self.cpu.zilch > 2) {
             self.cpu.zilch = 0;
             self.Interface.setCpu(self.cpu);
@@ -211,9 +211,9 @@ Game.prototype.rollDices = function(all) {
 /**
  * Toggle dice selection
  */
-Game.prototype.toggleDice = function(diceIndex) {
-  var self = this;
-  var dice = self.dices[diceIndex];
+Game.prototype.toggleDice = function (diceIndex) {
+  let self = this;
+  let dice = self.dices[diceIndex];
 
   if (!dice || dice.disabled) {
     console.error("This should not happen!")
@@ -222,15 +222,15 @@ Game.prototype.toggleDice = function(diceIndex) {
 
 
   dice.selected = !dice.selected;
-  var points = self.calculatePoints();
-  var valid = true;
+  let points = self.calculatePoints();
+  let valid = true;
 
-  for (var i = 0; i < 6; i++) {
-    var toggleDice = self.dices[i];
+  for (let i = 0; i < 6; i++) {
+    let toggleDice = self.dices[i];
 
     if (toggleDice.selected && !toggleDice.disabled) {
       toggleDice.selected = false;
-      var togglePoints = self.calculatePoints();
+      let togglePoints = self.calculatePoints();
       if (points > togglePoints) {
         toggleDice.invalid = false;
       } else if (togglePoints == points) {
@@ -265,21 +265,21 @@ Game.prototype.toggleDice = function(diceIndex) {
 /**
  * Calculate points on selected dices or all dices
  */
-Game.prototype.calculatePoints = function(all) {
-  var self = this;
-  var result = [0, 0, 0, 0, 0, 0];
-  for (var i = 0; i < 6; i++) {
-    var dice = self.dices[i];
+Game.prototype.calculatePoints = function (all) {
+  let self = this;
+  let result = [0, 0, 0, 0, 0, 0];
+  for (let i = 0; i < 6; i++) {
+    let dice = self.dices[i];
     if ((all || dice.selected) && !dice.disabled) {
       result[dice.value]++;
     }
   }
 
-  var straight = true;
-  var pairs = 0;
-  var triple1 = 0;
-  var triple2 = 0;
-  for (var i = 0; i < 6; i++) {
+  let straight = true;
+  let pairs = 0;
+  let triple1 = 0;
+  let triple2 = 0;
+  for (let i = 0; i < 6; i++) {
     straight &= (result[i] == 1);
     if (result[i] == 2) {
       pairs++;
@@ -290,15 +290,15 @@ Game.prototype.calculatePoints = function(all) {
       triple2 = i + 1;
     }
   }
-  var points = 0;
+  let points = 0;
 
   if (straight) {
     points += 1500;
   } else if (pairs == 3) {
     points += 1500;
   } else if (triple1) {
-    var triple1Points = triple1 * (triple1 == 1 ? 1000 : 100);
-    for (var i = 0; i < result[triple1 - 1] - 3; i++) {
+    let triple1Points = triple1 * (triple1 == 1 ? 1000 : 100);
+    for (let i = 0; i < result[triple1 - 1] - 3; i++) {
       triple1Points *= 2;
     }
     points += triple1Points;
@@ -324,13 +324,13 @@ Game.prototype.calculatePoints = function(all) {
 /**
  * Add points for current player
  */
-Game.prototype.addPoints = function() {
-  var self = this;
+Game.prototype.addPoints = function () {
+  let self = this;
 
   self.points += self.calculatePoints();
 
-  for (var i = 0; i < 6; i++) {
-    var dice = self.dices[i];
+  for (let i = 0; i < 6; i++) {
+    let dice = self.dices[i];
     if (dice.selected) {
       dice.selected = false;
       dice.disabled = true;
@@ -345,8 +345,8 @@ Game.prototype.addPoints = function() {
 /**
  * Take points and end round
  */
-Game.prototype.takePoints = function() {
-  var self = this;
+Game.prototype.takePoints = function () {
+  let self = this;
 
   self.addPoints();
 
@@ -354,7 +354,7 @@ Game.prototype.takePoints = function() {
     self.player.score += self.points;
     self.player.zilch = 0;
     self.Interface.setPlayer(self.player);
-    var history = {};
+    let history = {};
     history['player'] = self.points;
     self.history.push(history);
 
@@ -362,7 +362,7 @@ Game.prototype.takePoints = function() {
     self.cpu.score += self.points;
     self.cpu.zilch = 0;
     self.Interface.setCpu(self.cpu);
-    var history = {};
+    let history = {};
     history['cpu'] = self.points;
     self.history.push(history);
   }
@@ -378,13 +378,13 @@ Game.prototype.takePoints = function() {
 /**
  * End round for current player
  */
-Game.prototype.endRound = function() {
-  var self = this;
+Game.prototype.endRound = function () {
+  let self = this;
 
   self.newRound = true;
 
-  for (var i = 0; i < 6; i++) {
-    var dice = self.dices[i];
+  for (let i = 0; i < 6; i++) {
+    let dice = self.dices[i];
     if (dice.disabled) {
       dice.selected = true;
     } else {
@@ -400,7 +400,7 @@ Game.prototype.endRound = function() {
   self.Interface.setCpu(self.cpu);
 
   // check score
-  var checkScore = self.playing && self.cpuStarts || !self.playing && !self.cpuStarts;
+  let checkScore = self.playing && self.cpuStarts || !self.playing && !self.cpuStarts;
 
   if (checkScore && self.player.score >= 10000 && self.player.score > self.cpu.score) {
     self.Interface.disableRestart(false);
@@ -421,9 +421,9 @@ Game.prototype.endRound = function() {
       self.Interface.disableRestart(false);
       self.Interface.showMessage("Player's turn!");
     } else {
-      self.Interface.showMessage("CPU's turn!", self.messageTime, function() {
+      self.Interface.showMessage("CPU's turn!", self.messageTime, function () {
         if (!self.playing) {
-          setTimeout(function() {
+          setTimeout(function () {
             self.rollDices();
           }, self.cpuspeed);
         }
@@ -436,23 +436,23 @@ Game.prototype.endRound = function() {
 /**
  * CPU playing logic
  */
-Game.prototype.cpuPlay = function() {
-  var self = this;
+Game.prototype.cpuPlay = function () {
+  let self = this;
   self.Interface.disableRestart(true);
-  setTimeout(function() {
+  setTimeout(function () {
 
     // first select all available dices
-    for (var i = 0; i < 6; i++) {
-      var dice = self.dices[i];
+    for (let i = 0; i < 6; i++) {
+      let dice = self.dices[i];
       if (!dice.disabled) {
         self.toggleDice(i);
       }
     }
 
     // check if dice gains points
-    for (var i = 0; i < 6; i++) {
-      var dice = self.dices[i];
-      var tmpPoints = self.calculatePoints();
+    for (let i = 0; i < 6; i++) {
+      let dice = self.dices[i];
+      let tmpPoints = self.calculatePoints();
       if (!dice.disabled) {
         self.toggleDice(i);
         if (self.calculatePoints() < tmpPoints) {
@@ -462,17 +462,18 @@ Game.prototype.cpuPlay = function() {
     }
 
     // count free dices
-    var freeDices = 0;
-    for (var i = 0; i < 6; i++) {
-      var dice = self.dices[i];
+    let freeDices = 0;
+    for (let i = 0; i < 6; i++) {
+      let dice = self.dices[i];
       if (!dice.disabled && !dice.selected) {
         freeDices++;
       }
     }
 
-    setTimeout(function() {
+    setTimeout(function () {
+	  let cpuPoints = self.points + self.calculatePoints();
       // strategy: end round if points >= 300 and less than 4 dices left and not loosing
-      if (self.points + self.calculatePoints() >= 300 && freeDices < 4 && freeDices > 0 && self.player.score < 10000) {
+      if (cpuPoints >= 300 && freeDices < 4 && freeDices > 0 && (self.player.score < 10000 || (self.cpu.score + cpuPoints) > self.player.score)) {
         self.takePoints();
       } else {
         self.addPoints();
@@ -485,4 +486,4 @@ Game.prototype.cpuPlay = function() {
 }
 
 // create new game
-var game = new Game(Interface);
+let game = new Game(Interface);
\ No newline at end of file