diff --git a/OpenRA.Game/GameRules/ActorInfo.cs b/OpenRA.Game/GameRules/ActorInfo.cs
index 1c0e74c42b..1d7a79e1d9 100644
--- a/OpenRA.Game/GameRules/ActorInfo.cs
+++ b/OpenRA.Game/GameRules/ActorInfo.cs
@@ -31,7 +31,7 @@ namespace OpenRA
 		readonly TypeDictionary traits = new TypeDictionary();
 		List<ITraitInfo> constructOrderCache = null;
 
-		public ActorInfo(string name, MiniYaml node, Dictionary<string, MiniYaml> allUnits)
+		public ActorInfo(ObjectCreator creator, string name, MiniYaml node, Dictionary<string, MiniYaml> allUnits)
 		{
 			try
 			{
@@ -48,7 +48,7 @@ namespace OpenRA
 					if (t.Key != "Inherits" && !t.Key.StartsWith("Inherits@"))
 						try
 						{
-							traits.Add(LoadTraitInfo(t.Key.Split('@')[0], t.Value));
+							traits.Add(LoadTraitInfo(creator, t.Key.Split('@')[0], t.Value));
 						}
 						catch (FieldLoader.MissingFieldsException e)
 						{
@@ -99,12 +99,12 @@ namespace OpenRA
 			return node;
 		}
 
-		static ITraitInfo LoadTraitInfo(string traitName, MiniYaml my)
+		static ITraitInfo LoadTraitInfo(ObjectCreator creator, string traitName, MiniYaml my)
 		{
 			if (!string.IsNullOrEmpty(my.Value))
 				throw new YamlException("Junk value `{0}` on trait node {1}"
 				.F(my.Value, traitName));
-			var info = Game.CreateObject<ITraitInfo>(traitName + "Info");
+			var info = creator.CreateObject<ITraitInfo>(traitName + "Info");
 			try
 			{
 				FieldLoader.Load(info, my);
diff --git a/OpenRA.Game/GameRules/RulesetCache.cs b/OpenRA.Game/GameRules/RulesetCache.cs
index b5d53936c0..19cb3d83c7 100644
--- a/OpenRA.Game/GameRules/RulesetCache.cs
+++ b/OpenRA.Game/GameRules/RulesetCache.cs
@@ -61,7 +61,7 @@ namespace OpenRA
 			using (new PerfTimer("Actors"))
 				actors = LoadYamlRules(actorCache, m.Rules,
 					map != null ? map.RuleDefinitions : NoMapRules,
-					(k, y) => new ActorInfo(k.Key.ToLowerInvariant(), k.Value, y));
+					(k, y) => new ActorInfo(Game.ModData.ObjectCreator, k.Key.ToLowerInvariant(), k.Value, y));
 
 			using (new PerfTimer("Weapons"))
 				weapons = LoadYamlRules(weaponCache, m.Weapons,
diff --git a/OpenRA.Game/ModData.cs b/OpenRA.Game/ModData.cs
index 3bca6729ec..bfd345619e 100644
--- a/OpenRA.Game/ModData.cs
+++ b/OpenRA.Game/ModData.cs
@@ -12,6 +12,7 @@ using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
+using System.Reflection;
 using OpenRA.FileSystem;
 using OpenRA.Graphics;
 using OpenRA.Widgets;
@@ -38,7 +39,12 @@ namespace OpenRA
 		{
 			Languages = new string[0];
 			Manifest = new Manifest(mod);
-			ObjectCreator = new ObjectCreator(Manifest);
+
+			// Allow mods to load types from the core Game assembly, and any additional assemblies they specify.
+			var assemblies =
+				new[] { typeof(Game).Assembly }.Concat(
+					Manifest.Assemblies.Select(path => Assembly.LoadFrom(Platform.ResolvePath(path))));
+			ObjectCreator = new ObjectCreator(assemblies);
 			Manifest.LoadCustomData(ObjectCreator);
 
 			if (useLoadScreen)
diff --git a/OpenRA.Game/ObjectCreator.cs b/OpenRA.Game/ObjectCreator.cs
index e28636d6a4..ded80b27b2 100644
--- a/OpenRA.Game/ObjectCreator.cs
+++ b/OpenRA.Game/ObjectCreator.cs
@@ -22,24 +22,11 @@ namespace OpenRA
 		readonly Cache<Type, ConstructorInfo> ctorCache;
 		readonly Pair<Assembly, string>[] assemblies;
 
-		public ObjectCreator(Manifest manifest)
+		public ObjectCreator(IEnumerable<Assembly> sourceAssemblies)
 		{
 			typeCache = new Cache<string, Type>(FindType);
 			ctorCache = new Cache<Type, ConstructorInfo>(GetCtor);
-
-			// All the core namespaces
-			var asms = typeof(Game).Assembly.GetNamespaces() // Game
-				.Select(c => Pair.New(typeof(Game).Assembly, c))
-				.ToList();
-
-			// Namespaces from each mod assembly
-			foreach (var a in manifest.Assemblies)
-			{
-				var asm = Assembly.LoadFile(Platform.ResolvePath(a));
-				asms.AddRange(asm.GetNamespaces().Select(ns => Pair.New(asm, ns)));
-			}
-
-			assemblies = asms.ToArray();
+			assemblies = sourceAssemblies.SelectMany(asm => asm.GetNamespaces().Select(ns => Pair.New(asm, ns))).ToArray();
 		}
 
 		public static Action<string> MissingTypeAction =