diff --git a/commands1_input.txt b/commands1_input.txt
index 5fdb34b..3709e69 100644
--- a/commands1_input.txt
+++ b/commands1_input.txt
@@ -1,4 +1,5 @@
 build?
+draw
 list-buildings
 list-resources
 list-buildings I can build
diff --git a/commands1_output.txt b/commands1_output.txt
index de1d67f..c7cf735 100644
--- a/commands1_output.txt
+++ b/commands1_output.txt
@@ -1,4 +1,5 @@
 EMPTY
+Error, no card to draw exists
 EMPTY
 EMPTY
 Error, invalid list-buildings argument: none expected
diff --git a/game2_input.txt b/game2_input.txt
index 0ed3cff..2bab6cf 100644
--- a/game2_input.txt
+++ b/game2_input.txt
@@ -119,6 +119,8 @@ build shack
 build sailingraft
 rollD6 1
 build hangglider
+draw
 rollD6 3
+build anything
 list-buildings
 build ballon
diff --git a/game2_output.txt b/game2_output.txt
index 6987ad4..b2f0841 100644
--- a/game2_output.txt
+++ b/game2_output.txt
@@ -62,7 +62,9 @@ OK
 OK
 lose
 OK
+Error, roll dice, please
 lose
+Error, can not build item
 shack
 fireplace
 club
diff --git a/src/edu/kit/informatik/model/CardGame.java b/src/edu/kit/informatik/model/CardGame.java
index e305585..f6d2e2a 100644
--- a/src/edu/kit/informatik/model/CardGame.java
+++ b/src/edu/kit/informatik/model/CardGame.java
@@ -45,8 +45,7 @@ public class CardGame {
     public Card draw() throws InvalidInputException {
         if (cardStack == null || cardStack.isEmpty()) {
             throw new InvalidInputException("no card to draw exists");
-        }
-        if (awaitedDiceSize != null) {
+        } else if (awaitedDiceSize != null) {
             throw new InvalidInputException("roll dice, please");
         }
         Card card = cardStack.removeFirst();
@@ -66,22 +65,26 @@ public class CardGame {
     public String rollDice(int size, int roll) throws InvalidInputException {
         if (awaitedDiceSize == null) {
             throw new InvalidInputException("not expecting dice roll");
-        }
-        if (awaitedDiceSize != size) {
+        } else if (awaitedDiceSize != size) {
             throw new InvalidInputException("unexpected dice size");
+        } else if (roll > awaitedDiceSize || roll < 1) {
+            throw new InvalidInputException("impossible roll");
         }
+        awaitedDiceSize = null;
+        int minimumNeeded = minimumDiceRoll;
+        minimumDiceRoll = null;
         if (fightingAnimal) {
             int bonus = items.contains(AXE) ? 2 : items.contains(CLUB) ? 1 : 0;
-            if (roll + bonus >= minimumDiceRoll) {
+            if (roll + bonus >= minimumNeeded) {
                 return "survived";
             } else {
                 clearResources();
                 return "lose";
             }
-        } else {
+        } else { // attempting to escape
             // remove item used to escape
             items.remove(items.size() - 1);
-            if (roll >= minimumDiceRoll) {
+            if (roll >= minimumNeeded) {
                 return "win";
             } else {
                 return "lose";
@@ -98,12 +101,10 @@ public class CardGame {
 
     public boolean build(Item item) throws InvalidInputException {
         if (item == null) {
-            throw new InvalidInputException("can not build null item");
-        }
-        if (item.requiresFireplace() && !items.contains(FIREPLACE)) {
+            throw new InvalidInputException("can not build item");
+        } else if (item.requiresFireplace() && !items.contains(FIREPLACE)) {
             throw new InvalidInputException("need fireplace to build");
-        }
-        if (canBuild(item)) {
+        } else if (canBuild(item)) {
             // remove used resources
             for (Card resource : item.resourcesNeeded()) {
                 assert resources.removeLastOccurrence(resource); // TODO: remove assert
diff --git a/src/edu/kit/informatik/model/Item.java b/src/edu/kit/informatik/model/Item.java
index 7d663f4..336b17f 100644
--- a/src/edu/kit/informatik/model/Item.java
+++ b/src/edu/kit/informatik/model/Item.java
@@ -32,8 +32,8 @@ public enum Item {
                 return new Card[] {METAL, METAL, METAL, METAL, METAL, METAL, PLASTIC};
             case BALLOON:
                 return new Card[] {WOOD, PLASTIC, PLASTIC, PLASTIC, PLASTIC, PLASTIC, PLASTIC};
-            default:
-                return null;
+            default: // we don't have any such items, but could add some eventually
+                throw new IllegalArgumentException("item does not need resources");
         }
     }