diff --git a/OpenRa.Game/Chrome.cs b/OpenRa.Game/Chrome.cs
index 2c5ebb62f9..6e69caf944 100644
--- a/OpenRa.Game/Chrome.cs
+++ b/OpenRa.Game/Chrome.cs
@@ -703,7 +703,10 @@ namespace OpenRa.Game
 			p += new int2(0, 15);
 			if (!Rules.TechTree.CanBuild(info, Game.LocalPlayer, buildings))
 			{
-				var prereqs = info.Prerequisite.Select(a => Rules.UnitInfo[a.ToLowerInvariant()].Description);
+				var prereqs = info.Prerequisite
+					.Select(a => Rules.UnitInfo[a.ToLowerInvariant()])
+					.Where( u => u.Owner.Any( o => o == Game.LocalPlayer.Race ) )
+					.Select( a => a.Description );
 				renderer.DrawText("Requires {0}".F( string.Join( ", ", prereqs.ToArray() ) ), p.ToInt2(),
 					Color.White);
 			}
diff --git a/OpenRa.Game/Effects/Bullet.cs b/OpenRa.Game/Effects/Bullet.cs
index f342a2d76d..5104585dd3 100644
--- a/OpenRa.Game/Effects/Bullet.cs
+++ b/OpenRa.Game/Effects/Bullet.cs
@@ -31,6 +31,8 @@ namespace OpenRa.Game.Effects
 			FiredBy = firedBy;
 			Src = src;
 			Dest = dest;
+			SrcAltitude = srcAltitude;
+			DestAltitude = destAltitude;
 			VisualDest = Dest + new int2(
 						Game.CosmeticRandom.Next(-10, 10),
 						Game.CosmeticRandom.Next(-10, 10));
diff --git a/OpenRa.Game/GameRules/AftermathInfo.cs b/OpenRa.Game/GameRules/AftermathInfo.cs
index 96c403d00c..60511c4d5c 100644
--- a/OpenRa.Game/GameRules/AftermathInfo.cs
+++ b/OpenRa.Game/GameRules/AftermathInfo.cs
@@ -3,12 +3,12 @@ namespace OpenRa.Game.GameRules
 {
 	class AftermathInfo
 	{
-		public readonly int MTankDistance;
-		public readonly float QuakeUnitDamage;
-		public readonly float QuakeBuildingDamage;
-		public readonly float QuakeInfantryDamage;
-		public readonly int QuakeDelay;
-		public readonly int CarrierLaunchDelay;
-		public readonly int ChronoTankDuration;
+		public readonly int MTankDistance = 0;
+		public readonly float QuakeUnitDamage = 0f;
+		public readonly float QuakeBuildingDamage = 0f;
+		public readonly float QuakeInfantryDamage = 0f;
+		public readonly int QuakeDelay = 0;
+		public readonly int CarrierLaunchDelay = 0;
+		public readonly int ChronoTankDuration = 0;
 	}
 }
diff --git a/OpenRa.Game/GameRules/GeneralInfo.cs b/OpenRa.Game/GameRules/GeneralInfo.cs
index e351a7be66..cbd26f3d6b 100644
--- a/OpenRa.Game/GameRules/GeneralInfo.cs
+++ b/OpenRa.Game/GameRules/GeneralInfo.cs
@@ -1,126 +1,127 @@
 
+using System;
 namespace OpenRa.Game.GameRules
 {
 	class GeneralInfo
 	{
 		/* Crates */
-		public readonly int CrateMinimum;
-		public readonly int CrateMaximum;
-		public readonly float CrateRadius;
-		public readonly float CrateRegen;
-		public readonly string UnitCrateType;	/* =none, if any */
-		public readonly float WaterCrateChance;
+		public readonly int CrateMinimum = 0;
+		public readonly int CrateMaximum = 0;
+		public readonly float CrateRadius = 0;
+		public readonly float CrateRegen = 0;
+		public readonly string UnitCrateType = null;	/* =none, if any */
+		public readonly float WaterCrateChance = 0;
 
-		public readonly int SoloCrateMoney;
-		public readonly string SilverCrate;		/* solo play crate contents */
-		public readonly string WaterCrate;
-		public readonly string WoodCrate;
+		public readonly int SoloCrateMoney = 2000;
+		public readonly string SilverCrate = null;		/* solo play crate contents */
+		public readonly string WaterCrate = null;
+		public readonly string WoodCrate = null;
 
 		/* Special Weapons */
-		public readonly int ChronoDuration;
-		public readonly bool ChronoKillCargo;
-		public readonly int ChronoTechLevel;
-		public readonly int GPSTechLevel;
-		public readonly int GapRadius;
-		public readonly float GapRegenInterval;
-		public readonly float IronCurtain;		/* minutes */
-		public readonly int ParaTech;
-		public readonly int ParabombTech;
-		public readonly int RadarJamRadius;
-		public readonly int SpyPlaneTech;
-		public readonly int BadgerBombCount;
+		public readonly int ChronoDuration = 0;
+		public readonly bool ChronoKillCargo = true;
+		[Obsolete] public readonly int ChronoTechLevel = -1;
+		[Obsolete] public readonly int GPSTechLevel = -1;
+		public readonly int GapRadius = 0;
+		public readonly float GapRegenInterval =0;
+		public readonly float IronCurtain = 0;		/* minutes */
+		[Obsolete] public readonly int ParaTech = -1;
+		[Obsolete] public readonly int ParabombTech = -1;
+		public readonly int RadarJamRadius = 1;
+		[Obsolete] public readonly int SpyPlaneTech = -1;
+		public readonly int BadgerBombCount = 1;
 
 		/* Chrono Side Effects */
-		public readonly float QuakeChance;
-		public readonly float QuakeDamage;		/* percent */
-		public readonly float VortexChance;
-		public readonly int VortexDamage;
-		public readonly int VortexRange;
-		public readonly int VortexSpeed;
+		public readonly float QuakeChance = 0;
+		public readonly float QuakeDamage = 0;		/* percent */
+		public readonly float VortexChance = 0;
+		public readonly int VortexDamage = 0;
+		public readonly int VortexRange = 0;
+		public readonly int VortexSpeed = 0;
 
 		/* Repair & Refit */
-		public readonly float RefundPercent;
-		public readonly float ReloadRate;
-		public readonly float RepairPercent;
-		public readonly float RepairRate;
-		public readonly int RepairStep;
-		public readonly float URepairPercent;
-		public readonly int URepairStep;
+		public readonly float RefundPercent = 0;
+		public readonly float ReloadRate = 0;
+		public readonly float RepairPercent = 0;
+		public readonly float RepairRate = 0;
+		public readonly int RepairStep = 0;
+		public readonly float URepairPercent = 0;
+		public readonly int URepairStep = 0;
 
 		/* Combat & Damage */
-		public readonly float TurboBoost;
-		public readonly int APMineDamage;
-		public readonly int AVMineDamage;
-		public readonly int AtomDamage;
-		public readonly float BallisticScatter;
-		public readonly int BridgeStrength;
-		public readonly float C4Delay;
-		public readonly float Crush;
-		public readonly float ExpSpread;
-		public readonly int FireSupress;
-		public readonly float HomingScatter;
-		public readonly int MaxDamage;
-		public readonly int MinDamage;
-		public readonly bool OreExplosive;
-		public readonly bool PlayerAutoCrush;
-		public readonly bool PlayerReturnFire;
-		public readonly bool PlayerScatter;
-		public readonly float ProneDamage;
-		public readonly bool TreeTargeting;
-		public readonly int Incoming;
+		public readonly float TurboBoost = 1.5f;
+		public readonly int APMineDamage = 0;
+		public readonly int AVMineDamage = 0;
+		public readonly int AtomDamage = 0;
+		public readonly float BallisticScatter = 0;
+		public readonly int BridgeStrength = 0;
+		public readonly float C4Delay = 0;
+		public readonly float Crush = 0;
+		public readonly float ExpSpread = 0;
+		public readonly int FireSupress = 0;
+		public readonly float HomingScatter = 0;
+		public readonly int MaxDamage = 0;
+		public readonly int MinDamage = 0;
+		public readonly bool OreExplosive = false;
+		public readonly bool PlayerAutoCrush = false;
+		public readonly bool PlayerReturnFire = false;
+		public readonly bool PlayerScatter = false;
+		public readonly float ProneDamage = 0;
+		public readonly bool TreeTargeting = false;
+		public readonly int Incoming = 0;
 
 		/* Income & Production */
-		public readonly int BailCount;
-		public readonly float BuildSpeed;
-		public readonly float BuildupTime;
-		public readonly int GemValue;
-		public readonly int GoldValue;
-		public readonly float GrowthRate;
-		public readonly bool OreGrows;
-		public readonly bool OreSpreads;
-		public readonly float OreTruckRate;
-		public readonly bool SeparateAircraft;
-		public readonly float SurvivorRate;
+		public readonly int BailCount = 0;
+		public readonly float BuildSpeed = 0;
+		public readonly float BuildupTime = 0;
+		public readonly int GemValue = 0;
+		public readonly int GoldValue = 0;
+		public readonly float GrowthRate = 0;
+		public readonly bool OreGrows = true;
+		public readonly bool OreSpreads = true;
+		public readonly float OreTruckRate = 0;
+		public readonly bool SeparateAircraft = true;
+		public readonly float SurvivorRate = 0;
 
 		/* Audo/Visual Map Controls */
-		public readonly bool AllyReveal;
-		public readonly float ConditionRed;
-		public readonly float ConditionYellow;
-		public readonly int DropZoneRadius;
-		public readonly bool EnemyHealth;
-		public readonly int Gravity;
-		public readonly float IdleActionFrequency;
-		public readonly float MessageDelay;
-		public readonly float MovieTime;
-		public readonly bool NamedCivilians;
-		public readonly float SavourDelay;
-		public readonly int ShroudRate;
-		public readonly int SpeakDelay;
-		public readonly int TimerWarning;
-		public readonly bool FlashLowPower;
+		public readonly bool AllyReveal = true;
+		public readonly float ConditionRed = 0;
+		public readonly float ConditionYellow = 0;
+		public readonly int DropZoneRadius = 0;
+		public readonly bool EnemyHealth = true;
+		public readonly int Gravity = 0;
+		public readonly float IdleActionFrequency = 0;
+		public readonly float MessageDelay = 0;
+		public readonly float MovieTime = 0;
+		public readonly bool NamedCivilians = false;
+		public readonly float SavourDelay = 0;
+		public readonly int ShroudRate = 0;
+		public readonly int SpeakDelay = 0;
+		public readonly int TimerWarning = 0;
+		public readonly bool FlashLowPower = false;
 
 		/* Computer & Movement Controls */
-		public readonly bool CurleyShuffle;
-		public readonly float BaseBias;
-		public readonly float BaseDefenseDelay;
-		public readonly float CloseEnough;
-		public readonly int DamageDelay;
-		public readonly int GameSpeeBias;
-		public readonly int LZScanRadius;
-		public readonly bool MineAware;
-		public readonly float Stray;
-		public readonly float SubmergeDelay;
-		public readonly float SuspendDelay;
-		public readonly int SuspendPriority;
-		public readonly float TeamDelay;
+		public readonly bool CurleyShuffle = false;
+		public readonly float BaseBias = 0;
+		public readonly float BaseDefenseDelay = 0;
+		public readonly float CloseEnough = 0;
+		public readonly int DamageDelay = 0;
+		public readonly int GameSpeeBias = 0;
+		public readonly int LZScanRadius = 0;
+		public readonly bool MineAware = false;
+		public readonly float Stray = 0;
+		public readonly float SubmergeDelay = 0;
+		public readonly float SuspendDelay = 0;
+		public readonly int SuspendPriority = 0;
+		public readonly float TeamDelay = 0;
 
 		/* Misc */
-		public readonly bool FineDiffControl;
-		public readonly bool MCVUndeploy;
+		[Obsolete]
+		public readonly bool FineDiffControl = false;
+		public readonly bool MCVUndeploy = false;
 
 		/* OpenRA-specific */
-		public readonly float OreChance;	/* chance of spreading to a
-											 * particular eligible cell */
-		public readonly int LowPowerSlowdown;	/* build time multiplier */
+		public readonly float OreChance = 0;	/* chance of spreading to a particular eligible cell */
+		public readonly int LowPowerSlowdown = 3;	/* build time multiplier */
 	}
 }
diff --git a/OpenRa.Game/GameRules/TechTree.cs b/OpenRa.Game/GameRules/TechTree.cs
index 463934796e..af0fd79ce4 100755
--- a/OpenRa.Game/GameRules/TechTree.cs
+++ b/OpenRa.Game/GameRules/TechTree.cs
@@ -35,8 +35,9 @@ namespace OpenRa.Game.GameRules
 				return false;
 
 			foreach( var p in unit.Prerequisite )
-				if( playerBuildings[ p ].Count == 0 )
-					return false;
+				if (Rules.UnitInfo[p.ToLowerInvariant()].Owner.Any(x => x == player.Race))
+					if( playerBuildings[ p ].Count == 0 )
+						return false;
 
 			if( producesIndex[ Rules.UnitCategory[ unit.Name ] ].All( x => playerBuildings[ x.Name ].Count == 0 ) )
 				return false;
diff --git a/OpenRa.Game/GameRules/UnitInfo.cs b/OpenRa.Game/GameRules/UnitInfo.cs
index 7a29b23bb2..6054874fe0 100755
--- a/OpenRa.Game/GameRules/UnitInfo.cs
+++ b/OpenRa.Game/GameRules/UnitInfo.cs
@@ -1,4 +1,5 @@
 
+using System;
 namespace OpenRa.Game.GameRules
 {
 	public enum ArmorType
@@ -19,8 +20,8 @@ namespace OpenRa.Game.GameRules
 
 		public readonly int Ammo = -1;
 		public readonly ArmorType Armor = ArmorType.none;
-		public readonly bool DoubleOwned = false;
-		public readonly bool Cloakable = false;
+		[Obsolete] public readonly bool DoubleOwned = false;
+		[Obsolete] public readonly bool Cloakable = false;
 		public readonly int Cost = 0;
 		public readonly bool Crewed = false;
 		public readonly bool Explodes = false;
@@ -35,7 +36,7 @@ namespace OpenRa.Game.GameRules
 		public readonly int ROT = 255;
 		public readonly int Reload = 0;
 		public readonly bool SelfHealing = false;
-		public readonly bool Sensors = false; // no idea what this does
+		[Obsolete] public readonly bool Sensors = false; // no idea what this does
 		public readonly int Sight = 1;
 		public readonly int Strength = 1;
 		public readonly int TechLevel = -1;
diff --git a/doc/progress.txt b/doc/progress.txt
index ab2024c607..1d3b8f14f0 100644
--- a/doc/progress.txt
+++ b/doc/progress.txt
@@ -17,7 +17,7 @@ All tracked vehicles
 1TNK	Works
 2TNK	Works
 3TNK	Works
-4TNK	Gun, missile origins are wrong
+4TNK	Works
 
 Light vehicles
 V2RL	Works
diff --git a/rules.ini b/rules.ini
index 8c029a573e..34338ddc33 100644
--- a/rules.ini
+++ b/rules.ini
@@ -543,10 +543,9 @@ Armor=none
 TechLevel=2
 Sight=4
 Speed=3
-Owner=allies
+Owner=allies,soviet
 Cost=300
 Points=10
-DoubleOwned=yes
 
 ; Flamethrower
 [E4]
@@ -602,7 +601,7 @@ Infiltrate=yes
 
 ; Tanya
 [E7]
-Prerequisite=atek
+Prerequisite=atek,stek
 Primary=Colt45
 Secondary=Colt45
 Strength=100
@@ -615,7 +614,6 @@ Cost=1200
 Points=25
 Infiltrate=yes
 C4=yes
-DoubleOwned=yes
 
 ; field medic
 [MEDI]