diff --git a/Facepunch.Steamworks/Client.cs b/Facepunch.Steamworks/Client.cs
index 122be17..2e26673 100644
--- a/Facepunch.Steamworks/Client.cs
+++ b/Facepunch.Steamworks/Client.cs
@@ -12,6 +12,7 @@ public partial class Client : IDisposable
 
         internal Valve.Steamworks.ISteamClient _client;
         internal Valve.Steamworks.ISteamUser _user;
+        internal Valve.Steamworks.ISteamApps _apps;
         internal Valve.Steamworks.ISteamFriends _friends;
         internal Valve.Steamworks.ISteamMatchmakingServers _servers;
         internal Valve.Steamworks.ISteamInventory _inventory;
@@ -32,6 +33,17 @@ public partial class Client : IDisposable
         /// </summary>
         public ulong SteamId;
 
+        public enum MessageType : int
+        {
+            Message = 0,
+            Warning = 1
+        }
+
+        /// <summary>
+        /// Called with a message from Steam
+        /// </summary>
+        public Action<MessageType, string> OnMessage;
+
         public Client( uint appId )
         {
             Valve.Steamworks.SteamAPI.Init( appId );
@@ -46,7 +58,7 @@ public Client( uint appId )
             //
             // Set up warning hook callback
             //
-            SteamAPIWarningMessageHook ptr = OnWarning;
+            SteamAPIWarningMessageHook ptr = InternalOnWarning;
             _client.SetWarningMessageHook( Marshal.GetFunctionPointerForDelegate( ptr ) );
 
             //
@@ -64,6 +76,7 @@ public Client( uint appId )
             _servers = _client.GetISteamMatchmakingServers( _huser, _hpipe, "SteamMatchMakingServers002" );
             _inventory = _client.GetISteamInventory( _huser, _hpipe, "STEAMINVENTORY_INTERFACE_V001" );
             _networking = _client.GetISteamNetworking( _huser, _hpipe, "SteamNetworking005" );
+            _apps = _client.GetISteamApps( _huser, _hpipe, "STEAMAPPS_INTERFACE_VERSION008" );
 
             AppId = appId;
             Username = _friends.GetPersonaName();
@@ -95,9 +108,12 @@ public void Dispose()
         [UnmanagedFunctionPointer( CallingConvention.Cdecl )]
         public delegate void SteamAPIWarningMessageHook( int nSeverity, System.Text.StringBuilder pchDebugText );
 
-        private void OnWarning( int nSeverity, System.Text.StringBuilder text )
+        private void InternalOnWarning( int nSeverity, System.Text.StringBuilder text )
         {
-            Console.Write( text.ToString() );
+            if ( OnMessage != null )
+            {
+                OnMessage( ( MessageType)nSeverity, text.ToString() );
+            }
         }
 
         /// <summary>
diff --git a/Facepunch.Steamworks/Client/App.cs b/Facepunch.Steamworks/Client/App.cs
new file mode 100644
index 0000000..7dd6556
--- /dev/null
+++ b/Facepunch.Steamworks/Client/App.cs
@@ -0,0 +1,40 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace Facepunch.Steamworks
+{
+    public partial class Client : IDisposable
+    {
+        App _app;
+
+        public App App
+        {
+            get
+            {
+                if ( _app == null )
+                    _app = new App( this );
+
+                return _app;
+            }
+        }
+    }
+
+    public class App
+    {
+        internal Client client;
+
+        internal App( Client c )
+        {
+            client = c;
+        }
+
+        public void MarkContentCorrupt( bool missingFilesOnly = false )
+        {
+            client._apps.MarkContentCorrupt( missingFilesOnly );
+        }
+
+
+    }
+}
diff --git a/Facepunch.Steamworks/Facepunch.Steamworks.csproj b/Facepunch.Steamworks/Facepunch.Steamworks.csproj
index b6e4825..e3130b5 100644
--- a/Facepunch.Steamworks/Facepunch.Steamworks.csproj
+++ b/Facepunch.Steamworks/Facepunch.Steamworks.csproj
@@ -120,6 +120,7 @@
     <Compile Include="Client.Voice.cs" />
     <Compile Include="Client.Auth.cs" />
     <Compile Include="Client.cs" />
+    <Compile Include="Client\App.cs" />
     <Compile Include="Client\Inventory.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="steam_api_interop.cs" />
diff --git a/Facepunch.Steamworks/steam_api_interop.cs b/Facepunch.Steamworks/steam_api_interop.cs
index 98afd33..7b819f4 100644
--- a/Facepunch.Steamworks/steam_api_interop.cs
+++ b/Facepunch.Steamworks/steam_api_interop.cs
@@ -2469,7 +2469,7 @@ internal override ISteamApps GetISteamApps( uint hSteamUser, uint hSteamPipe, st
         {
             CheckIfUsable();
             IntPtr result = NativeEntrypoints.SteamAPI_ISteamClient_GetISteamApps(m_pSteamClient,hSteamUser,hSteamPipe,pchVersion);
-            return (ISteamApps)Marshal.PtrToStructure( result, typeof( ISteamApps ) );
+            return new CSteamApps( result );
         }
         internal override ISteamNetworking GetISteamNetworking( uint hSteamUser, uint hSteamPipe, string pchVersion )
         {