diff --git a/source/Game.cpp b/source/Game.cpp
index 6473e57..2201403 100644
--- a/source/Game.cpp
+++ b/source/Game.cpp
@@ -27,7 +27,7 @@ Game::Game(sf::RenderWindow& window) :
 	mWindow.setKeyRepeatEnabled(true);
 
 	Generator generator;
-	generator.generateTiles(mTileManager, sf::IntRect(-10, -10, 20, 20));
+	generator.generateTiles(mTileManager, sf::IntRect(-20, -20, 40, 40));
 	mPlayer = std::shared_ptr<Player>(new Player(mWorld, mTileManager,
 			sf::Vector2f(0.0f, 0.0f), Yaml("player.yaml")));
 	mWorld.insertCharacter(mPlayer);
diff --git a/source/World.cpp b/source/World.cpp
index 0da96ab..50c35da 100755
--- a/source/World.cpp
+++ b/source/World.cpp
@@ -262,11 +262,14 @@ World::heuristic_cost_estimate(Area* start, Area* end) const {
 void
 World::step(int elapsed) {
 	for (auto v = mDrawables.begin(); v != mDrawables.end(); v++) {
-		for (auto it = v->second.begin(); it != v->second.end(); ) {
+		for (auto it = v->second.begin(); it != v->second.end(); it++) {
 			auto spriteA = *it;
-			if (spriteA->getDelete())
+			if (spriteA->getDelete()) {
 				remove(spriteA);
-			else {
+				it--;
+			}
+			// Apply movement for movable sprites.
+			else if ((*it)->isMovable()) {
 				sf::Vector2f speed = spriteA->getSpeed();
 				speed *= elapsed / 1000.0f;
 				bool overlap = false;
@@ -286,7 +289,6 @@ World::step(int elapsed) {
 				}
 				if (!overlap)
 					spriteA->setPosition(spriteA->getPosition() + speed);
-				it++;
 			}
 		}
 	}
diff --git a/source/abstract/Sprite.cpp b/source/abstract/Sprite.cpp
index 4f0d819..b29003f 100755
--- a/source/abstract/Sprite.cpp
+++ b/source/abstract/Sprite.cpp
@@ -153,6 +153,15 @@ Sprite::collisionEnabled(Category category) const {
 	return (category & mMask) != 0;
 }
 
+/**
+ * Returns true if this sprite is able to move, currently decided by shape
+ * (circle can move, rectangle can not).
+ */
+bool
+Sprite::isMovable() const {
+	return mShape.type == Shape::Type::CIRCLE;
+}
+
 /**
  * Called when a collision with another Sprite occured. Override this method
  * to manage collision events.
diff --git a/source/abstract/Sprite.h b/source/abstract/Sprite.h
index cb7f087..5f98b64 100755
--- a/source/abstract/Sprite.h
+++ b/source/abstract/Sprite.h
@@ -67,6 +67,7 @@ public:
 	sf::Vector2f getSize() const;
 	virtual void draw(sf::RenderTarget& target, sf::RenderStates states) const;
 	bool collisionEnabled(Category category) const;
+	bool isMovable() const;
 
 	virtual void onCollide(std::shared_ptr<Sprite> other);