Expanding on Ideas: Mall Rats

When I read Ratcatcher's pitch for a Maze Rats game set in a procedurally-generated dead mall, I was absolutely enamored with the concept, and had ideas on how to expand on it. So without further ado, here we go.

• A small part of the mall denizens are made up of people like the PCs: those who are trapped and still have free will. Typically teenagers or young adults, these people have formed themselves into factions resembling social cliques. The goths, the preps, the jocks, etc. Some neckbearded nerds don swords and anime attire, dubbing themselves "mall ninjas". They lord over the others, seemingly within the good graces of security.
• These factions tend to be somewhat secretive, as security is constantly watching for those who aren't a part of the mall, so finding them out and contacting them may prove to be a difficult task.
• The majority of mall denizens are "normal people" who walk around and shop. These beings are ghosts of those who have died in the mall, and have zero free will. They are cursed to wander and shop and eat for all eternity. If they see suspicious activity, they will call security. If a PC dies in the mall, they become part of it. The party may even see dead characters occasionally buying food or seeing a movie. Attempting to interact with them may result in security being called, however.
  
• Security are manifestations of the mall and can range from simple adult humans to other things entirely, pulled from different realities. The deeper the players go into the mall, the more bizarre things get.
• The mall pulls things from different times, places, and even universes. You may be in a simple large corridor with some mid-80s stores, then walk into a food court where the menus are all in German and the calendar says 2052. The mall actively gives the middle finger to space and time. Some areas may be abandoned and overgrown, where worse things than security lurk.
• Magic is very much a thing in this place, but to perform magic you must find a skateboard. Skateboards allow you to manipulate the forces of the mall's reality with sheer rad x-treme awesomeness. Grinding on rails, getting mad air, etc. will amplify your spell effects. If you aren't on your board or not moving, you cannot cast spells. Riding a skateboard in places that you're not supposed to be is grounds for security to be called.
• Weapons are limited so the PCs have to get creative. Hot coffee grenades, soda and mentos bombs, slingshots, popcorn caltrops, bottle rockets, socks filled with arcade tokens, etc. Think like Home Alone or Monster Squad when allowing weapons. A simple chair leg is effective, sure, but what about a tennis ball filled with tacks?
• Food, equipment, etc. can be purchased from the stores. PCs can heal by consuming junk food, candy, and pizza. Money is rare and must either be found, stolen, or won in arcades.
• PCs can find backrooms, hallways, and utility passages between stores. These locations are dangerous, rife with security and traps, but can lead to shortcuts to other areas. Rarely, security offices can appear in these hallways which have good equipment and weapons inside.
• Taking elevators can lead to different levels of reality, including a floor for meeting rooms, or down to the dreaded parking garage. The PCs may only escape out of the parking garage, which contains very dangerous enemies and is as random as the mall. The players must come prepared in order to survive.

I'll expand on this more as I think on stuff. If you have suggestions, throw them down in the comments. Thanks for reading!