diff --git a/app/controllers/break_escape/games_controller.rb b/app/controllers/break_escape/games_controller.rb
index d634951..dad53f4 100644
--- a/app/controllers/break_escape/games_controller.rb
+++ b/app/controllers/break_escape/games_controller.rb
@@ -2,7 +2,7 @@ require 'open3'
 
 module BreakEscape
   class GamesController < ApplicationController
-    before_action :set_game, only: [:show, :scenario, :ink, :room, :sync_state, :unlock, :inventory]
+    before_action :set_game, only: [:show, :scenario, :scenario_map, :ink, :room, :container, :sync_state, :unlock, :inventory]
 
     def show
       authorize @game if defined?(Pundit)
@@ -16,6 +16,31 @@ module BreakEscape
       render json: @game.scenario_data
     end
 
+    # GET /games/:id/scenario_map
+    # Returns minimal scenario metadata for navigation (no room contents)
+    def scenario_map
+      authorize @game if defined?(Pundit)
+
+      # Return minimal room/connection metadata without contents
+      layout = {}
+      @game.scenario_data['rooms'].each do |room_id, room_data|
+        layout[room_id] = {
+          type: room_data['type'],
+          connections: room_data['connections'] || {},
+          locked: room_data['locked'] || false,
+          lockType: room_data['lockType'],
+          hasNPCs: (room_data['npcs']&.length || 0) > 0,
+          accessible: @game.room_unlocked?(room_id)
+        }
+      end
+
+      render json: {
+        startRoom: @game.scenario_data['startRoom'],
+        currentRoom: @game.player_state['currentRoom'],
+        rooms: layout
+      }
+    end
+
     # GET /games/:id/room/:room_id
     # Returns room data for a specific room (lazy-loading support)
     def room
@@ -24,16 +49,63 @@ module BreakEscape
       room_id = params[:room_id]
       return render_error('Missing room_id parameter', :bad_request) unless room_id.present?
 
-      # Get room data from scenario
-      room_data = @game.scenario_data['rooms']&.[](room_id)
+      # Check if room is accessible (starting room OR in unlockedRooms)
+      is_start_room = @game.scenario_data['startRoom'] == room_id
+      is_unlocked = @game.player_state['unlockedRooms']&.include?(room_id)
+
+      unless is_start_room || is_unlocked
+        return render_error("Room not accessible: #{room_id}", :forbidden)
+      end
+
+      # Auto-add start room if missing (defensive programming)
+      if is_start_room && !is_unlocked
+        @game.player_state['unlockedRooms'] ||= []
+        @game.player_state['unlockedRooms'] << room_id
+        @game.save!
+      end
+
+      # Get and filter room data
+      room_data = @game.filtered_room_data(room_id)
       return render_error("Room not found: #{room_id}", :not_found) unless room_data
 
+      # Track NPC encounters BEFORE sending response
+      track_npc_encounters(room_id, room_data)
+
       Rails.logger.debug "[BreakEscape] Serving room data for: #{room_id}"
 
-      # Return room data with the room_id for client reference
       render json: { room_id: room_id, room: room_data }
     end
 
+    # GET /games/:id/container/:container_id
+    # Returns container contents after unlock (lazy-loaded)
+    def container
+      authorize @game if defined?(Pundit)
+
+      container_id = params[:container_id]
+      return render_error('Missing container_id parameter', :bad_request) unless container_id.present?
+
+      # Find container in scenario data
+      container_data = find_container_in_scenario(container_id)
+      return render_error("Container not found: #{container_id}", :not_found) unless container_data
+
+      # Check if container is unlocked (check multiple possible identifiers)
+      is_unlocked = check_container_unlocked(container_id, container_data)
+
+      unless is_unlocked
+        return render_error("Container not unlocked: #{container_id}", :forbidden)
+      end
+
+      # Return filtered contents
+      contents = filter_container_contents(container_data)
+
+      Rails.logger.debug "[BreakEscape] Serving container contents for: #{container_id}"
+
+      render json: {
+        container_id: container_id,
+        contents: contents
+      }
+    end
+
     # GET /games/:id/ink?npc=helper1
     # Returns NPC script (JIT compiled if needed)
     def ink
@@ -78,7 +150,16 @@ module BreakEscape
 
       # Update allowed fields
       if params[:currentRoom]
-        @game.player_state['currentRoom'] = params[:currentRoom]
+        # Verify room is accessible
+        if @game.player_state['unlockedRooms'].include?(params[:currentRoom]) ||
+           @game.scenario_data['startRoom'] == params[:currentRoom]
+          @game.player_state['currentRoom'] = params[:currentRoom]
+        else
+          return render json: {
+            success: false,
+            message: "Cannot enter locked room: #{params[:currentRoom]}"
+          }, status: :forbidden
+        end
       end
 
       if params[:globalVariables]
@@ -102,9 +183,18 @@ module BreakEscape
 
       is_valid = @game.validate_unlock(target_type, target_id, attempt, method)
 
-      if is_valid
+      unless is_valid
+        return render json: {
+          success: false,
+          message: 'Invalid attempt'
+        }, status: :unprocessable_entity
+      end
+
+      # Use transaction to ensure atomic update
+      ActiveRecord::Base.transaction do
         if target_type == 'door'
           @game.unlock_room!(target_id)
+
           room_data = @game.filtered_room_data(target_id)
 
           render json: {
@@ -113,18 +203,20 @@ module BreakEscape
             roomData: room_data
           }
         else
+          # Object/container unlock
           @game.unlock_object!(target_id)
+
           render json: {
             success: true,
             type: 'object'
           }
         end
-      else
-        render json: {
-          success: false,
-          message: 'Invalid attempt'
-        }, status: :unprocessable_entity
       end
+    rescue ActiveRecord::RecordInvalid => e
+      render json: {
+        success: false,
+        message: "Failed to save unlock: #{e.message}"
+      }, status: :unprocessable_entity
     end
 
     # POST /games/:id/inventory
@@ -137,11 +229,20 @@ module BreakEscape
 
       case action_type
       when 'add'
+        # Validate item exists and is collectible
+        validation_error = validate_item_collectible(item)
+        if validation_error
+          return render json: { success: false, message: validation_error },
+                       status: :unprocessable_entity
+        end
+
         @game.add_inventory_item!(item.to_unsafe_h)
         render json: { success: true, inventory: @game.player_state['inventory'] }
+
       when 'remove'
         @game.remove_inventory_item!(item['id'])
         render json: { success: true, inventory: @game.player_state['inventory'] }
+
       else
         render json: { success: false, message: 'Invalid action' }, status: :bad_request
       end
@@ -153,6 +254,195 @@ module BreakEscape
       @game = Game.find(params[:id])
     end
 
+    def track_npc_encounters(room_id, room_data)
+      return unless room_data['npcs'].present?
+
+      npc_ids = room_data['npcs'].map { |npc| npc['id'] }
+      @game.player_state['encounteredNPCs'] ||= []
+
+      new_npcs = npc_ids - @game.player_state['encounteredNPCs']
+      return if new_npcs.empty?
+
+      @game.player_state['encounteredNPCs'].concat(new_npcs)
+      @game.save!
+
+      Rails.logger.debug "[BreakEscape] Tracked NPC encounters: #{new_npcs.join(', ')}"
+    end
+
+    def find_container_in_scenario(container_id)
+      @game.scenario_data['rooms'].each do |room_id, room_data|
+        # Search objects for container
+        container = find_container_recursive(room_data['objects'], container_id)
+        return container if container
+
+        # Search nested contents
+        room_data['objects']&.each do |obj|
+          container = search_nested_contents(obj['contents'], container_id)
+          return container if container
+        end
+      end
+      nil
+    end
+
+    def find_container_recursive(objects, container_id)
+      return nil unless objects
+
+      objects.each do |obj|
+        # Check if this object matches
+        if obj['id'] == container_id || (obj['name'] && obj['name'] == container_id)
+          return obj if obj['contents'].present?
+        end
+
+        # Recursively search nested contents
+        nested = find_container_recursive(obj['contents'], container_id)
+        return nested if nested
+      end
+      nil
+    end
+
+    def search_nested_contents(contents, container_id)
+      return nil unless contents
+
+      contents.each do |item|
+        return item if (item['id'] == container_id || item['name'] == container_id) && item['contents'].present?
+        nested = search_nested_contents(item['contents'], container_id)
+        return nested if nested
+      end
+      nil
+    end
+
+    def check_container_unlocked(container_id, container_data)
+      unlocked_list = @game.player_state['unlockedObjects'] || []
+
+      # Check multiple possible identifiers
+      unlocked_list.include?(container_id) ||
+      unlocked_list.include?(container_data['id']) ||
+      unlocked_list.include?(container_data['name']) ||
+      unlocked_list.include?(container_data['type'])
+    end
+
+    def filter_container_contents(container_data)
+      contents = container_data['contents']&.map do |item|
+        item_copy = item.deep_dup
+        @game.send(:filter_requires_and_contents_recursive, item_copy)
+        item_copy
+      end || []
+
+      contents
+    end
+
+    def validate_item_collectible(item)
+      item_type = item['type']
+      item_id = item['id']
+
+      # Search scenario for this item
+      found_item = find_item_in_scenario(item_type, item_id)
+      return "Item not found in scenario: #{item_type}" unless found_item
+
+      # Check if item is takeable
+      unless found_item['takeable']
+        return "Item is not takeable: #{found_item['name']}"
+      end
+
+      # If item is in locked container, check if container is unlocked
+      container_info = find_item_container(item_type, item_id)
+      if container_info.present?
+        container_id = container_info[:id]
+        unless @game.player_state['unlockedObjects'].include?(container_id)
+          return "Container not unlocked: #{container_id}"
+        end
+      end
+
+      # If item is in locked room, check if room is unlocked
+      room_info = find_item_room(item_type, item_id)
+      if room_info.present?
+        room_id = room_info[:id]
+        if room_info[:locked] && !@game.player_state['unlockedRooms'].include?(room_id)
+          return "Room not unlocked: #{room_id}"
+        end
+      end
+
+      # Check if NPC holds this item and if NPC encountered
+      npc_info = find_npc_holding_item(item_type, item_id)
+      if npc_info.present?
+        npc_id = npc_info[:id]
+        unless @game.player_state['encounteredNPCs'].include?(npc_id)
+          return "NPC not encountered: #{npc_id}"
+        end
+      end
+
+      nil # No error
+    end
+
+    def find_item_in_scenario(item_type, item_id)
+      @game.scenario_data['rooms'].each do |room_id, room_data|
+        # Search room objects
+        room_data['objects']&.each do |obj|
+          return obj if obj['type'] == item_type && (obj['id'] == item_id || obj['name'] == item_id)
+
+          # Search nested contents
+          obj['contents']&.each do |content|
+            return content if content['type'] == item_type && (content['id'] == item_id || content['name'] == item_id)
+          end
+        end
+      end
+      nil
+    end
+
+    def find_item_container(item_type, item_id)
+      @game.scenario_data['rooms'].each do |room_id, room_data|
+        room_data['objects']&.each do |obj|
+          obj['contents']&.each do |content|
+            if content['type'] == item_type && (content['id'] == item_id || content['name'] == item_id)
+              return { id: obj['id'] || obj['name'], locked: obj['locked'] }
+            end
+          end
+        end
+      end
+      nil
+    end
+
+    def find_item_room(item_type, item_id)
+      @game.scenario_data['rooms'].each do |room_id, room_data|
+        room_data['objects']&.each do |obj|
+          if obj['type'] == item_type && (obj['id'] == item_id || obj['name'] == item_id)
+            return { id: room_id, locked: room_data['locked'] }
+          end
+        end
+      end
+      nil
+    end
+
+    def find_npc_holding_item(item_type, item_id)
+      @game.scenario_data['rooms'].each do |room_id, room_data|
+        room_data['npcs']&.each do |npc|
+          next unless npc['itemsHeld'].present?
+
+          # itemsHeld is array of full item objects (same structure as room objects)
+          npc['itemsHeld'].each do |held_item|
+            # Match by type (required) and optionally by id/name
+            if held_item['type'] == item_type
+              # If item_id provided, verify it matches
+              if item_id.present?
+                item_matches = (held_item['id'] == item_id) ||
+                              (held_item['name'] == item_id) ||
+                              (item_id == item_type) # Fallback if no id field
+                next unless item_matches
+              end
+
+              return {
+                id: npc['id'],
+                npc: npc,
+                item: held_item,
+                type: 'npc'
+              }
+            end
+          end
+        end
+      end
+      nil
+    end
+
     def find_npc_in_scenario(npc_id)
       available_npcs = []
       @game.scenario_data['rooms']&.each do |room_id, room_data|
diff --git a/app/models/break_escape/game.rb b/app/models/break_escape/game.rb
index 0da0fde..4c7e6a8 100644
--- a/app/models/break_escape/game.rb
+++ b/app/models/break_escape/game.rb
@@ -131,16 +131,9 @@ module BreakEscape
       room = room_data(room_id)&.deep_dup
       return nil unless room
 
-      # Remove solutions
-      room.delete('requires')
-      room.delete('lockType') if room['locked']
-
-      # Remove solutions from objects
-      room['objects']&.each do |obj|
-        obj.delete('requires')
-        obj.delete('lockType') if obj['locked']
-        obj.delete('contents') if obj['locked']
-      end
+      # Remove ONLY the 'requires' field (the solution) and locked 'contents'
+      # Keep lockType, locked, observations visible to client
+      filter_requires_and_contents_recursive(room)
 
       room
     end
@@ -182,6 +175,27 @@ module BreakEscape
 
     private
 
+    def filter_requires_and_contents_recursive(obj)
+      case obj
+      when Hash
+        # Remove 'requires' (the answer/solution)
+        obj.delete('requires')
+
+        # Remove 'contents' if locked (lazy-loaded via separate endpoint)
+        obj.delete('contents') if obj['locked']
+
+        # Keep lockType - client needs it to show correct UI
+        # Keep locked - client needs it to show lock status
+
+        # Recursively filter nested objects and NPCs
+        obj['objects']&.each { |o| filter_requires_and_contents_recursive(o) }
+        obj['npcs']&.each { |n| filter_requires_and_contents_recursive(n) }
+
+      when Array
+        obj.each { |item| filter_requires_and_contents_recursive(item) }
+      end
+    end
+
     def generate_scenario_data
       self.scenario_data = mission.generate_scenario_data
     end
@@ -192,6 +206,14 @@ module BreakEscape
       self.player_state['unlockedRooms'] ||= [scenario_data['startRoom']]
       self.player_state['unlockedObjects'] ||= []
       self.player_state['inventory'] ||= []
+
+      # Initialize starting items from scenario
+      if scenario_data['startItemsInInventory'].present?
+        scenario_data['startItemsInInventory'].each do |item|
+          self.player_state['inventory'] << item.deep_dup
+        end
+      end
+
       self.player_state['encounteredNPCs'] ||= []
       self.player_state['globalVariables'] ||= {}
       self.player_state['biometricSamples'] ||= []
diff --git a/config/routes.rb b/config/routes.rb
index e12079a..fcd5f30 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -15,9 +15,11 @@ BreakEscape::Engine.routes.draw do
   resources :games, only: [:show, :create] do
     member do
       # Scenario and NPC data
-      get 'scenario'  # Returns scenario_data JSON
-      get 'ink'       # Returns NPC script (JIT compiled)
-      get 'room/:room_id', to: 'games#room'  # Returns room data for lazy-loading
+      get 'scenario'          # Returns full scenario_data JSON (for compatibility)
+      get 'scenario_map'      # Returns minimal layout metadata for navigation
+      get 'ink'               # Returns NPC script (JIT compiled)
+      get 'room/:room_id', to: 'games#room'            # Returns room data for lazy-loading
+      get 'container/:container_id', to: 'games#container'  # Returns locked container contents
 
       # Game state and actions
       put 'sync_state'    # Periodic state sync
diff --git a/public/break_escape/js/api-client.js b/public/break_escape/js/api-client.js
index 6940718..5c7c891 100644
--- a/public/break_escape/js/api-client.js
+++ b/public/break_escape/js/api-client.js
@@ -68,11 +68,16 @@ export class ApiClient {
     return response.json();
   }
 
-  // Get scenario JSON
+  // Get scenario JSON (full scenario data)
   static async getScenario() {
     return this.get('/scenario');
   }
 
+  // Get scenario map (minimal layout metadata for navigation)
+  static async getScenarioMap() {
+    return this.get('/scenario_map');
+  }
+
   // Get NPC script
   static async getNPCScript(npcId) {
     return this.get(`/ink?npc=${npcId}`);
diff --git a/public/break_escape/js/core/game.js b/public/break_escape/js/core/game.js
index 71a074d..c5acfbc 100644
--- a/public/break_escape/js/core/game.js
+++ b/public/break_escape/js/core/game.js
@@ -441,9 +441,9 @@ export function preload() {
 
     // Load scenario from Rails API endpoint if available, otherwise try URL parameter
     if (window.breakEscapeConfig?.apiBasePath) {
-        // Load scenario from Rails API endpoint
+        // Load scenario map from Rails API endpoint (minimal metadata for lazy-loading)
         // Use absolute URL with origin to prevent Phaser baseURL from interfering
-        const scenarioUrl = `${window.location.origin}${window.breakEscapeConfig.apiBasePath}/scenario`;
+        const scenarioUrl = `${window.location.origin}${window.breakEscapeConfig.apiBasePath}/scenario_map`;
         this.load.json('gameScenarioJSON', scenarioUrl);
     } else {
         // Fallback to old behavior for standalone HTML files
diff --git a/public/break_escape/js/minigames/container/container-minigame.js b/public/break_escape/js/minigames/container/container-minigame.js
index 6a24e27..ed56a07 100644
--- a/public/break_escape/js/minigames/container/container-minigame.js
+++ b/public/break_escape/js/minigames/container/container-minigame.js
@@ -24,23 +24,64 @@ export class ContainerMinigame extends MinigameScene {
         const containerName = this.containerItem?.scenarioData?.name?.toLowerCase() || '';
         const containerType = this.containerItem?.scenarioData?.type?.toLowerCase() || '';
         const containerImage = this.containerItem?.name?.toLowerCase() || '';
-        
+
         // Keywords that indicate desktop/computer devices
         const desktopKeywords = [
             'computer', 'pc', 'laptop', 'desktop', 'terminal', 'workstation',
             'tablet', 'ipad', 'surface', 'monitor', 'screen', 'display',
             'server', 'mainframe', 'console', 'kiosk', 'smartboard'
         ];
-        
+
         // Check if any keyword matches
         const allText = `${containerName} ${containerType} ${containerImage}`.toLowerCase();
         return desktopKeywords.some(keyword => allText.includes(keyword));
     }
-    
-    init() {
+
+    async loadContainerContents() {
+        const gameId = window.gameId;
+        const containerId = this.containerItem.scenarioData.id ||
+                           this.containerItem.scenarioData.name ||
+                           this.containerItem.objectId;
+
+        if (!gameId) {
+            console.error('No gameId available for container loading');
+            return [];
+        }
+
+        console.log(`Loading contents for container: ${containerId}`);
+
+        try {
+            const response = await fetch(`/break_escape/games/${gameId}/container/${containerId}`, {
+                headers: { 'Accept': 'application/json' }
+            });
+
+            if (!response.ok) {
+                if (response.status === 403) {
+                    if (window.gameAlert) {
+                        window.gameAlert('Container is locked', 'error', 'Locked', 2000);
+                    }
+                    this.complete(false);
+                    return [];
+                }
+                throw new Error(`HTTP ${response.status}: ${response.statusText}`);
+            }
+
+            const data = await response.json();
+            console.log(`Loaded ${data.contents?.length || 0} items from container`);
+            return data.contents || [];
+        } catch (error) {
+            console.error('Failed to load container contents:', error);
+            if (window.gameAlert) {
+                window.gameAlert('Could not load container contents', 'error', 'Error', 3000);
+            }
+            return [];
+        }
+    }
+
+    async init() {
         // Call parent init first
         super.init();
-        
+
         // Update header with container name
         if (this.headerElement) {
             this.headerElement.innerHTML = `
@@ -48,7 +89,7 @@ export class ContainerMinigame extends MinigameScene {
                 <p>${this.containerItem.scenarioData.observations || ''}</p>
             `;
         }
-        
+
         // Add notebook button to minigame controls if postit note exists (before cancel button)
         if (this.controlsElement && this.containerItem.scenarioData.postitNote && this.containerItem.scenarioData.showPostit) {
             const notebookBtn = document.createElement('button');
@@ -58,7 +99,16 @@ export class ContainerMinigame extends MinigameScene {
             // Insert before the cancel button (first child in controls)
             this.controlsElement.insertBefore(notebookBtn, this.controlsElement.firstChild);
         }
-        
+
+        // Show loading state
+        this.gameContainer.innerHTML = '<div class="loading" style="text-align: center; padding: 20px;">Loading contents...</div>';
+
+        // Load contents from server (if gameId exists and container is not locked)
+        if (window.gameId && this.containerItem.scenarioData.locked === false) {
+            this.contents = await this.loadContainerContents();
+        }
+        // Otherwise use contents passed in (for unlocked containers or local game)
+
         // Create the container minigame UI
         this.createContainerUI();
     }
diff --git a/public/break_escape/js/systems/inventory.js b/public/break_escape/js/systems/inventory.js
index d3452f8..6614de8 100644
--- a/public/break_escape/js/systems/inventory.js
+++ b/public/break_escape/js/systems/inventory.js
@@ -188,12 +188,12 @@ function createInventorySprite(itemData) {
     }
 }
 
-export function addToInventory(sprite) {
+export async function addToInventory(sprite) {
     if (!sprite || !sprite.scenarioData) {
         console.warn('Invalid sprite for inventory');
         return false;
     }
-    
+
     try {
         console.log("Adding to inventory:", {
             objectId: sprite.objectId,
@@ -201,18 +201,57 @@ export function addToInventory(sprite) {
             type: sprite.scenarioData?.type,
             currentRoom: window.currentPlayerRoom
         });
-        
-        // Check if the item is already in the inventory
+
+        // Check if the item is already in the inventory (local check first)
         const itemIdentifier = createItemIdentifier(sprite.scenarioData);
-        const isAlreadyInInventory = window.inventory.items.some(item => 
+        const isAlreadyInInventory = window.inventory.items.some(item =>
             item && createItemIdentifier(item.scenarioData) === itemIdentifier
         );
-        
+
         if (isAlreadyInInventory) {
             console.log(`Item ${itemIdentifier} is already in inventory`);
             return false;
         }
-        
+
+        // NEW: Validate with server before adding
+        const gameId = window.gameId;
+        if (gameId) {
+            try {
+                const response = await fetch(`/break_escape/games/${gameId}/inventory`, {
+                    method: 'POST',
+                    headers: {
+                        'Content-Type': 'application/json',
+                        'Accept': 'application/json'
+                    },
+                    body: JSON.stringify({
+                        action_type: 'add',
+                        item: sprite.scenarioData
+                    })
+                });
+
+                const result = await response.json();
+
+                if (!result.success) {
+                    // Server rejected - show error to player
+                    console.warn('Server rejected inventory add:', result.message);
+                    if (window.gameAlert) {
+                        window.gameAlert(result.message || 'Cannot collect this item', 'error', 'Invalid Action', 3000);
+                    }
+                    return false;
+                }
+
+                // Server accepted - continue with local inventory update
+                console.log('Server validated item collection:', result);
+            } catch (error) {
+                console.error('Failed to validate inventory with server:', error);
+                // Fail closed - don't add if server can't validate
+                if (window.gameAlert) {
+                    window.gameAlert('Network error - please try again', 'error', 'Error', 3000);
+                }
+                return false;
+            }
+        }
+
         // Remove from room if it exists
         if (window.currentPlayerRoom && rooms[window.currentPlayerRoom] && rooms[window.currentPlayerRoom].objects) {
             if (rooms[window.currentPlayerRoom].objects[sprite.objectId]) {