As an AI language model, I can provide you with a basic template for an HTML file that includes JavaScript to create a game where you can free roam a city and interact with AI NPCs. Here is the code:
This code sets up a simple city roam game where you control a blue square representing the player. The green squares represent AI Non-Playable Characters (NPCs). You can move around the city using the arrow keys. When the player collides with an NPC, a console message is printed indicating the interaction. Feel free to modify the code to add additional features, graphics, or AI responses to suit your needs.