diff --git a/Shared/NPC.cs b/Shared/NPC.cs
index bbf6d66..cbca207 100644
--- a/Shared/NPC.cs
+++ b/Shared/NPC.cs
@@ -15,14 +15,24 @@ namespace SemiColinGames {
 
     public int Facing { get; private set; } = 1;
 
-    public void Update(float modelTime) {
-      if (Facing == 1 && position.X > 16 * 39) {
-        Facing = -1;
+    public void Update(float modelTime, AABB[] collisionTargets) {
+      int moveSpeed = 120;
+      int desiredX = position.X + (int) (moveSpeed * Facing * modelTime);
+      // TODO: define the box modularly & correctly.
+      AABB npcBox = new AABB(new Vector2(desiredX, position.Y), new Vector2(11, 33));
+      Debug.AddRect(npcBox, Color.Cyan);
+      bool foundBox = false;
+      foreach (AABB box in collisionTargets) {
+        if (box.Intersect(npcBox) != null) {
+          foundBox = true;
+          break;
+        }
       }
-      if (Facing == -1 && position.X < 16 * 24) {
-        Facing = 1;
+
+      if (!foundBox) {
+        Facing *= -1;
       }
-      position.X += (int) (120 * Facing * modelTime);
+      position.X = desiredX;
     }
 
     public void Draw(SpriteBatch spriteBatch) {
diff --git a/Shared/Player.cs b/Shared/Player.cs
index 7f0f438..2591abb 100644
--- a/Shared/Player.cs
+++ b/Shared/Player.cs
@@ -48,7 +48,7 @@ namespace SemiColinGames {
 
     public Point Position { get { return position; } }
 
-    public void Update(float modelTime, History<Input> input, AABB[] collisionTargets) {
+    public void Update(float modelTime, AABB[] collisionTargets, History<Input> input) {
       AABB BoxOffset(Point position, int yOffset) {
         return new AABB(new Vector2(position.X, position.Y + yOffset), halfSize);
       }
diff --git a/Shared/World.cs b/Shared/World.cs
index 1a8704c..d752231 100644
--- a/Shared/World.cs
+++ b/Shared/World.cs
@@ -90,7 +90,7 @@ namespace SemiColinGames {
     public const int TileSize = 16;
     readonly Tile[] tiles;
     readonly Tile[] decorations;
-    readonly NPC[] npcs = new NPC[1];
+    readonly NPC[] npcs = new NPC[4];
 
     // Size of World in terms of tile grid.
     private readonly int tileWidth;
@@ -109,7 +109,11 @@ namespace SemiColinGames {
 
     public World(string levelSpecification) {
       Player = new Player();
-      npcs[0] = new NPC(new Point(16 * 38, 16 * 12));
+      npcs[0] = new NPC(new Point(16 * 8, 16 * 6));
+      npcs[1] = new NPC(new Point(16 * 28, 16 * 6));
+      npcs[2] = new NPC(new Point(16 * 36, 16 * 6));
+      npcs[3] = new NPC(new Point(16 * 36, 16 * 12));
+
       var tilesList = new List<Tile>();
       var decorationsList = new List<Tile>();
       string[] worldDesc = levelSpecification.Substring(1).Split('\n');
@@ -158,9 +162,9 @@ namespace SemiColinGames {
     }
 
     public void Update(float modelTime, History<Input> input) {
-      Player.Update(modelTime, input, CollisionTargets);
+      Player.Update(modelTime, CollisionTargets, input);
       foreach (NPC npc in npcs) {
-        npc.Update(modelTime);
+        npc.Update(modelTime, CollisionTargets);
       }
       if (Player.Health <= 0) {
         Reset();