diff --git a/source/collada/CommonConvert.cpp b/source/collada/CommonConvert.cpp
index 6998e21c0c..3d7a5e702c 100644
--- a/source/collada/CommonConvert.cpp
+++ b/source/collada/CommonConvert.cpp
@@ -204,7 +204,7 @@ static bool IsVisible_XSI(FCDSceneNode* node, bool& visible)
 
 static bool IsVisible(FCDSceneNode* node)
 {
-	bool visible;
+	bool visible = false;
 
 	// Try the XSI visibility property
 	if (IsVisible_XSI(node, visible))
diff --git a/source/gui/CGUI.cpp b/source/gui/CGUI.cpp
index 66db1f17fc..7d0636b230 100644
--- a/source/gui/CGUI.cpp
+++ b/source/gui/CGUI.cpp
@@ -513,7 +513,7 @@ void CGUI::Draw()
 	glPopMatrix();
 }
 
-void CGUI::DrawSprite(CGUISpriteInstance& Sprite,
+void CGUI::DrawSprite(const CGUISpriteInstance& Sprite,
 					  int CellID,
 					  const float& Z,
 					  const CRect& Rect,
diff --git a/source/gui/CGUI.h b/source/gui/CGUI.h
index b0aee80ba3..d6c77f3770 100644
--- a/source/gui/CGUI.h
+++ b/source/gui/CGUI.h
@@ -148,7 +148,7 @@ public:
 	 * @param Rect Position and Size
 	 * @param Clipping The sprite shouldn't be drawn outside this rectangle
 	 */
-	void DrawSprite(CGUISpriteInstance& Sprite, int CellID, const float &Z, 
+	void DrawSprite(const CGUISpriteInstance& Sprite, int CellID, const float &Z, 
 					const CRect &Rect, const CRect &Clipping=CRect());
 
 	/**
diff --git a/source/gui/CGUIScrollBarVertical.cpp b/source/gui/CGUIScrollBarVertical.cpp
index 70f5884f10..2e9b5bf1a7 100644
--- a/source/gui/CGUIScrollBarVertical.cpp
+++ b/source/gui/CGUIScrollBarVertical.cpp
@@ -67,7 +67,7 @@ void CGUIScrollBarVertical::Draw()
 		if (m_UseEdgeButtons)
 		{
 			// Get Appropriate sprites
-			CGUISpriteInstance *button_top, *button_bottom;
+			const CGUISpriteInstance *button_top, *button_bottom;
 
 			// figure out what sprite to use for top button
 			if (m_ButtonMinusHovered)
diff --git a/source/gui/CGUISprite.cpp b/source/gui/CGUISprite.cpp
index 132a2c3afb..54e68bac86 100644
--- a/source/gui/CGUISprite.cpp
+++ b/source/gui/CGUISprite.cpp
@@ -18,7 +18,7 @@
 #include "precompiled.h"
 #include "CGUISprite.h"
 
-void CGUISpriteInstance::Draw(CRect Size, int CellID, std::map<CStr, CGUISprite> &Sprites)
+void CGUISpriteInstance::Draw(CRect Size, int CellID, std::map<CStr, CGUISprite> &Sprites) const
 {
 	if (m_CachedSize != Size || m_CachedCellID != CellID)
 	{
diff --git a/source/gui/CGUISprite.h b/source/gui/CGUISprite.h
index 611286492f..d239e59ed8 100644
--- a/source/gui/CGUISprite.h
+++ b/source/gui/CGUISprite.h
@@ -156,7 +156,7 @@ public:
 	CGUISpriteInstance(const CStr& SpriteName);
 	CGUISpriteInstance(const CGUISpriteInstance &Sprite);
 	CGUISpriteInstance &operator=(const CStr& SpriteName);
-	void Draw(CRect Size, int CellID, std::map<CStr, CGUISprite> &Sprites);
+	void Draw(CRect Size, int CellID, std::map<CStr, CGUISprite> &Sprites) const;
 	void Invalidate();
 	bool IsEmpty() const;
 	const CStr& GetName() { return m_SpriteName; }
@@ -165,11 +165,11 @@ private:
 	CStr m_SpriteName;
 
 	// Stored drawing calls, for more efficient rendering
-	GUIRenderer::DrawCalls m_DrawCallCache;
+	mutable GUIRenderer::DrawCalls m_DrawCallCache;
 	// Relevant details of previously rendered sprite; the cache is invalidated
 	// whenever any of these values changes.
-	CRect m_CachedSize;
-	int m_CachedCellID;
+	mutable CRect m_CachedSize;
+	mutable int m_CachedCellID;
 };
 
 #endif
diff --git a/source/gui/GUIRenderer.cpp b/source/gui/GUIRenderer.cpp
index a185cab05b..bea43c8f00 100644
--- a/source/gui/GUIRenderer.cpp
+++ b/source/gui/GUIRenderer.cpp
@@ -344,7 +344,7 @@ public:
 
 // Functions to perform drawing-related actions:
 
-void GUIRenderer::UpdateDrawCallCache(DrawCalls &Calls, CStr& SpriteName, CRect &Size, int CellID, std::map<CStr, CGUISprite> &Sprites)
+void GUIRenderer::UpdateDrawCallCache(DrawCalls &Calls, const CStr& SpriteName, const CRect &Size, int CellID, std::map<CStr, CGUISprite> &Sprites)
 {
 	// This is called only when something has changed (like the size of the
 	// sprite), so it doesn't need to be particularly efficient.
diff --git a/source/gui/GUIRenderer.h b/source/gui/GUIRenderer.h
index 8a94fd2148..9ea4a4f434 100644
--- a/source/gui/GUIRenderer.h
+++ b/source/gui/GUIRenderer.h
@@ -69,7 +69,7 @@ namespace GUIRenderer
 
 namespace GUIRenderer
 {
-	void UpdateDrawCallCache(DrawCalls &Calls, CStr&SpriteName, CRect& Size, int CellID, std::map<CStr, CGUISprite> &Sprites);
+	void UpdateDrawCallCache(DrawCalls &Calls, const CStr& SpriteName, const CRect& Size, int CellID, std::map<CStr, CGUISprite> &Sprites);
 
 	void Draw(DrawCalls &Calls);
 }
diff --git a/source/gui/GUIutil.cpp b/source/gui/GUIutil.cpp
index f3ca795684..1456de8349 100644
--- a/source/gui/GUIutil.cpp
+++ b/source/gui/GUIutil.cpp
@@ -291,7 +291,8 @@ void CInternalCGUIAccessorBase::HandleMessage(IGUIObject *pObject, const SGUIMes
 #ifndef NDEBUG
 	#define TYPE(T) \
 		template<> void CheckType<T>(const IGUIObject* obj, const CStr& setting) {	\
-			if (((IGUIObject*)obj)->m_Settings[setting].m_Type != GUIST_##T)	\
+			std::map<CStr, SGUISetting>::const_iterator it = obj->m_Settings.find(setting);	\
+			if (it == obj->m_Settings.end() || it->second.m_Type != GUIST_##T)	\
 			{	\
 				/* Abort now, to avoid corrupting everything by invalidly \
 					casting pointers */ \
diff --git a/source/gui/GUIutil.h b/source/gui/GUIutil.h
index 157b60bd42..f16ace598b 100644
--- a/source/gui/GUIutil.h
+++ b/source/gui/GUIutil.h
@@ -222,9 +222,9 @@ public:
 	 * @param sec Secondary sprite if Primary should fail
 	 * @return Resulting string
 	 */
-	static CGUISpriteInstance& FallBackSprite(
-									CGUISpriteInstance& prim,
-									CGUISpriteInstance& sec)
+	static const CGUISpriteInstance& FallBackSprite(
+									const CGUISpriteInstance& prim,
+									const CGUISpriteInstance& sec)
 	{
 		// CStr() == empty string, null
 		return (prim.IsEmpty() ? sec : prim);
diff --git a/source/gui/IGUIScrollBar.cpp b/source/gui/IGUIScrollBar.cpp
index 704439eb2b..128328b166 100644
--- a/source/gui/IGUIScrollBar.cpp
+++ b/source/gui/IGUIScrollBar.cpp
@@ -50,7 +50,7 @@ void IGUIScrollBar::SetupBarSize()
 	m_BarSize = std::min((float)m_ScrollSpace/(float)m_ScrollRange, 1.f);
 }
 
-SGUIScrollBarStyle *IGUIScrollBar::GetStyle() const
+const SGUIScrollBarStyle *IGUIScrollBar::GetStyle() const
 {
 	if (!m_pHostObject)
 		return NULL;
diff --git a/source/gui/IGUIScrollBar.h b/source/gui/IGUIScrollBar.h
index ce3378dcd6..3516a1de95 100644
--- a/source/gui/IGUIScrollBar.h
+++ b/source/gui/IGUIScrollBar.h
@@ -304,7 +304,7 @@ public:
 	 * Get style used by the scrollbar
 	 * @return Scroll bar style struct.
 	 */
-	SGUIScrollBarStyle * GetStyle() const;
+	const SGUIScrollBarStyle * GetStyle() const;
 
 	/**
 	 * Get the rectangle of the actual BAR. not the whole scroll-bar.
diff --git a/source/gui/IGUIScrollBarOwner.cpp b/source/gui/IGUIScrollBarOwner.cpp
index 65836a7577..5511d4a7d7 100644
--- a/source/gui/IGUIScrollBarOwner.cpp
+++ b/source/gui/IGUIScrollBarOwner.cpp
@@ -58,21 +58,22 @@ void IGUIScrollBarOwner::AddScrollBar(IGUIScrollBar * scrollbar)
 	m_ScrollBars.push_back(scrollbar);
 }
 
-SGUIScrollBarStyle * IGUIScrollBarOwner::GetScrollBarStyle(const CStr& style) const
+const SGUIScrollBarStyle * IGUIScrollBarOwner::GetScrollBarStyle(const CStr& style) const
 {
 	if (!GetGUI())
 	{
 		// TODO Gee: Output in log
 		return NULL;
 	}
-	
-	if (GetGUI()->m_ScrollBarStyles.count(style) == 0)
+
+	std::map<CStr, SGUIScrollBarStyle>::const_iterator it = GetGUI()->m_ScrollBarStyles.find(style);
+	if (it == GetGUI()->m_ScrollBarStyles.end())
 	{
 		// TODO Gee: Output in log
 		return NULL;
 	}
 
- 	return &((CGUI*)GetGUI())->m_ScrollBarStyles.find(style)->second;
+ 	return &it->second;
 }
 
 void IGUIScrollBarOwner::HandleMessage(const SGUIMessage &Message)
diff --git a/source/gui/IGUIScrollBarOwner.h b/source/gui/IGUIScrollBarOwner.h
index d010b26ed8..de8ea4951d 100644
--- a/source/gui/IGUIScrollBarOwner.h
+++ b/source/gui/IGUIScrollBarOwner.h
@@ -81,7 +81,7 @@ public:
 	/**
 	 * Interface for the m_ScrollBar to use.
 	 */
-	virtual SGUIScrollBarStyle *GetScrollBarStyle(const CStr& style) const;
+	virtual const SGUIScrollBarStyle *GetScrollBarStyle(const CStr& style) const;
 
 	/**
 	 * Add a scroll-bar
diff --git a/source/i18n/CLocale.cpp b/source/i18n/CLocale.cpp
index e216d77de7..c90c78b33c 100644
--- a/source/i18n/CLocale.cpp
+++ b/source/i18n/CLocale.cpp
@@ -109,7 +109,7 @@ bool CLocale::LoadStrings(const char* data)
 					u8 NameLength = *(u8*)data;
 					data += 1;
 
-					std::string NameText ((char*)data, (char*)(data + NameLength));
+					std::string NameText ((const char*)data, (const char*)(data + NameLength));
 					data += NameLength;
 
 					u8 ParamCount = *(u8*)data;
diff --git a/source/lib/allocators/string_pool.cpp b/source/lib/allocators/string_pool.cpp
index 0d155db72e..10d023cf39 100644
--- a/source/lib/allocators/string_pool.cpp
+++ b/source/lib/allocators/string_pool.cpp
@@ -55,11 +55,11 @@ const char* StringPool::UniqueCopy(const char* string)
 		return existingString;
 
 	const size_t length = strlen(string);
-	const char* uniqueCopy = (const char*)pool_alloc(&m_pool, length+1);
+	char* uniqueCopy = (char*)pool_alloc(&m_pool, length+1);
 	if(!uniqueCopy)
 		throw std::bad_alloc();
 	cpu_memcpy((void*)uniqueCopy, string, length);
-	((char*)uniqueCopy)[length] = '\0';
+	uniqueCopy[length] = '\0';
 
 	m_map.insert(uniqueCopy, uniqueCopy);
 
diff --git a/source/scripting/DOMEvent.cpp b/source/scripting/DOMEvent.cpp
index a6525bb604..3739834e29 100644
--- a/source/scripting/DOMEvent.cpp
+++ b/source/scripting/DOMEvent.cpp
@@ -77,9 +77,9 @@ bool IEventTarget::_DispatchEvent( CScriptEvent* evt, IEventTarget* target )
 // returns: whether the event arrived (i.e. wasn't cancelled) [bool]
 bool IEventTarget::DispatchEvent( CScriptEvent* evt )
 {
-	char* data;
+	const char* data;
 	PROFILE_START( "intern string" );
-	data = (char*) g_Profiler.InternString( "script: " + (CStr8)evt->m_Type );
+	data = g_Profiler.InternString( "script: " + (CStr8)evt->m_Type );
 	PROFILE_END( "intern string" );
 	g_Profiler.StartScript( data );
 	evt->m_Target = this;
diff --git a/source/scripting/SpiderMonkey.h b/source/scripting/SpiderMonkey.h
index 25472e088d..8b5cc16b6c 100644
--- a/source/scripting/SpiderMonkey.h
+++ b/source/scripting/SpiderMonkey.h
@@ -15,6 +15,9 @@
  * along with 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#ifndef INCLUDED_SPIDERMONKEY
+#define INCLUDED_SPIDERMONKEY
+
 // Master header for the SpiderMonkey Javascript library.
 //
 // Include this instead of accessing any <js*.h> headers directly.
@@ -58,3 +61,5 @@
 #ifndef NDEBUG
 # define JS_AddRoot(cx, rp) JS_AddNamedRoot((cx), (rp), __FILE__ )
 #endif
+
+#endif // INCLUDED_SPIDERMONKEY
diff --git a/source/simulation/EntitySupport.h b/source/simulation/EntitySupport.h
index 753c50a73c..7ab5cb86f6 100644
--- a/source/simulation/EntitySupport.h
+++ b/source/simulation/EntitySupport.h
@@ -25,8 +25,8 @@
 struct SEntityAction
 {
 	int m_Id;
-	float m_MaxRange;
 	float m_MinRange;
+	float m_MaxRange;
 	int m_Speed;
 	CStr8 m_Animation;
 	SEntityAction()
diff --git a/source/tools/atlas/AtlasUI/Misc/DLLInterface.h b/source/tools/atlas/AtlasUI/Misc/DLLInterface.h
index 4971bfc161..526a05132c 100644
--- a/source/tools/atlas/AtlasUI/Misc/DLLInterface.h
+++ b/source/tools/atlas/AtlasUI/Misc/DLLInterface.h
@@ -15,6 +15,9 @@
  * along with 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#ifndef DLLINTERFACE_INCLUDED
+#define DLLINTERFACE_INCLUDED
+
 #include <wchar.h>
 
 namespace AtlasMessage { class MessagePasser; }
@@ -31,4 +34,4 @@ ATLASDLLIMPEXP void Atlas_DisplayError(const wchar_t* text, size_t flags);
 
 ATLASDLLIMPEXP void Atlas_ReportError();
 
-ATLASDLLIMPEXP void Atlas_ReportError();
+#endif // DLLINTERFACE_INCLUDED