diff --git a/src/Items/CreativeBuilding.cs b/src/Items/CreativeBuilding.cs
index 725d84d..26b5125 100644
--- a/src/Items/CreativeBuilding.cs
+++ b/src/Items/CreativeBuilding.cs
@@ -113,6 +113,10 @@ public class CreativeBuilding : Node2D
     {
         if (Player.NetworkID != GetTree().GetRpcSenderId()) return;
 
+        // TODO: Make sure position is a reasonable distance away.
+        if (!Enum.IsDefined(typeof(Facing), direction)) return;
+        if ((length < 1) || (length > MaxLength)) return;
+
         // TODO: Test if starting block is valid.
         // FIXME: Test if there is a player in the way.
 
@@ -130,7 +134,9 @@ public class CreativeBuilding : Node2D
     {
         if (Player.NetworkID != GetTree().GetRpcSenderId()) return;
 
-        // TODO: Do additional verification on the packet.
+        // TODO: Make sure position is a reasonable distance away.
+        if (!Enum.IsDefined(typeof(Facing), direction)) return;
+        if ((length < 1) || (length > MaxLength)) return;
 
         var start = new BlockPos(x, y);
         var world = this.GetWorld();
diff --git a/src/Items/Weapon.cs b/src/Items/Weapon.cs
index 7fac9d2..1b5b1f4 100644
--- a/src/Items/Weapon.cs
+++ b/src/Items/Weapon.cs
@@ -153,8 +153,8 @@ public class Weapon : Sprite
     {
         if (this.GetGame() is Server) {
             if (Player.NetworkID != GetTree().GetRpcSenderId()) return;
-            // TODO: Verify input.
-            // if ((value < 0) || (value > Mathf.Tau)) return;
+            if (float.IsNaN(value = Mathf.PosMod(value, Mathf.Tau))) return;
+
             RPC.Unreliable(SendAimAngle, value);
         } else if (!(Player is LocalPlayer))
             AimDirection = value;
@@ -204,7 +204,8 @@ public class Weapon : Sprite
     {
         if (this.GetGame() is Server) {
             if (Player.NetworkID != GetTree().GetRpcSenderId()) return;
-            // TODO: Verify input.
+            if (float.IsNaN(aimDirection = Mathf.PosMod(aimDirection, Mathf.Tau))) return;
+
             if (FireInternal(aimDirection, toRight, seed))
                 RPC.Reliable(SendFire, aimDirection, toRight, seed);
         } else if (!(Player is LocalPlayer))
diff --git a/src/Objects/Player.cs b/src/Objects/Player.cs
index fb8c3c4..20c6fd8 100644
--- a/src/Objects/Player.cs
+++ b/src/Objects/Player.cs
@@ -52,7 +52,9 @@ public class Player : KinematicBody2D, IInitializable
     public void ChangeAppearance(string displayName, Color color)
     {
         if (GetTree().GetRpcSenderId() != NetworkID) return;
-        // TODO: Validate input.
+        if (displayName == null) return;
+        // TODO: Verify display name some more.
+        if (color.a < 1.0F) return;
 
         Rset(nameof(DisplayName), displayName);
         Rset(nameof(Color), color);
diff --git a/src/Scenes/Server.cs b/src/Scenes/Server.cs
index c83eda8..eef08b6 100644
--- a/src/Scenes/Server.cs
+++ b/src/Scenes/Server.cs
@@ -1,7 +1,6 @@
 using System;
 using Godot;
 
-// TODO: Allow for initially private integrated server to open itself up to the public.
 public class Server : Game
 {
     internal Player LocalPlayer { get; private set; }
@@ -20,11 +19,11 @@ public class Server : Game
 
     public ushort StartSingleplayer()
     {
+        // TODO: When get_local_port is available, just use port 0 for an auto-assigned port.
+        //       Also see this PR: https://github.com/godotengine/godot/pull/48235
         for (var retries = 0; ; retries++) {
             try {
                 IsSingleplayer = true;
-                // TODO: When `get_local_port` is available, just use port 0 for an auto-assigned port.
-                //       Also see this PR: https://github.com/godotengine/godot/pull/48235
                 var port = (ushort)GD.RandRange(42000, 43000);
                 Start(port, "127.0.0.1", 1);
                 return port;