diff --git a/OpenRa.Game/OpenRa.Game.csproj b/OpenRa.Game/OpenRa.Game.csproj
index bae8b5e563..04bd69d3ed 100644
--- a/OpenRa.Game/OpenRa.Game.csproj
+++ b/OpenRa.Game/OpenRa.Game.csproj
@@ -1,4 +1,4 @@
-<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003" ToolsVersion="3.5">
+<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003" ToolsVersion="3.5">
   <PropertyGroup>
     <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
     <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
@@ -109,6 +109,7 @@
     <Compile Include="Traits\AcceptsOre.cs" />
     <Compile Include="Traits\Activities\Attack.cs" />
     <Compile Include="Traits\Activities\Circle.cs" />
+    <Compile Include="Traits\Activities\Demolish.cs" />
     <Compile Include="Traits\Activities\Fly.cs" />
     <Compile Include="Traits\Activities\FlyTimed.cs" />
     <Compile Include="Traits\Activities\IActivity.cs" />
@@ -176,6 +177,7 @@
     <Compile Include="Traits\AutoTarget.cs" />
     <Compile Include="Traits\BelowUnits.cs" />
     <Compile Include="Traits\Building.cs" />
+    <Compile Include="Traits\C4Demolition.cs" />
     <Compile Include="Traits\Explodes.cs" />
     <Compile Include="Traits\ChronoshiftDeploy.cs" />
     <Compile Include="Traits\Fake.cs" />
@@ -267,4 +269,4 @@
   <Target Name="AfterBuild">
   </Target>
   -->
-</Project>
+</Project>
\ No newline at end of file
diff --git a/OpenRa.Game/Traits/Activities/Demolish.cs b/OpenRa.Game/Traits/Activities/Demolish.cs
new file mode 100644
index 0000000000..ef6cdedeb8
--- /dev/null
+++ b/OpenRa.Game/Traits/Activities/Demolish.cs
@@ -0,0 +1,30 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace OpenRa.Game.Traits.Activities
+{
+	class Demolish : IActivity
+	{
+		Actor target;
+		public IActivity NextActivity { get; set; }
+
+		public Demolish( Actor target )
+		{
+			this.target = target;
+		}
+
+		public IActivity Tick(Actor self)
+		{
+			if (target == null || target.IsDead) return NextActivity;
+
+			// 1. run to adj tile
+			// 2. spawn timed demolition (for +3/4s)
+			// 3. run away --- where?
+			return this;
+		}
+
+		public void Cancel(Actor self) { target = null; NextActivity = null; }
+	}
+}
diff --git a/OpenRa.Game/Traits/C4Demolition.cs b/OpenRa.Game/Traits/C4Demolition.cs
new file mode 100644
index 0000000000..db3fa2bced
--- /dev/null
+++ b/OpenRa.Game/Traits/C4Demolition.cs
@@ -0,0 +1,29 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using OpenRa.Game.Traits.Activities;
+
+namespace OpenRa.Game.Traits
+{
+	class C4Demolition : IOrder
+	{
+		public Order IssueOrder(Actor self, int2 xy, MouseInput mi, Actor underCursor)
+		{
+			if (underCursor == null) return null;
+			if (underCursor.Owner == self.Owner && !mi.Modifiers.HasModifier(Modifiers.Ctrl)) return null;
+			if (!underCursor.traits.Contains<Building>()) return null;
+
+			return new Order("C4", self, underCursor, int2.Zero, null);
+		}
+
+		public void ResolveOrder(Actor self, Order order)
+		{
+			if (order.OrderString == "C4")
+			{
+				self.CancelActivity();
+				self.QueueActivity(new Demolish(order.TargetActor));
+			}
+		}
+	}
+}
diff --git a/doc/progress.txt b/doc/progress.txt
index fa8cf9e94e..c38a818d43 100644
--- a/doc/progress.txt
+++ b/doc/progress.txt
@@ -8,7 +8,7 @@ E3		Works
 E4		Flamer origin is wrong
 E6		Capture action missing, repair action missing
 E7		C4 action missing
-MEDI	Heal targeting is wrong
+MEDI	Works
 SPY		Infiltrate action missing
 THF		Steal action missing
 C1,C2,Einstein,Kosygin		Not implemented
@@ -47,7 +47,7 @@ MIG		Weapons don't work
 Ships
 CA		Works
 SS		Works
-DD		AA weapon doesn't work, depth charges don't work
+DD		depth charges don't work
 PT		depth charges don't work
 LST		Cargo doesn't work