How about more film related munchies such as crisps and tortilla chips, chocolate and drinks.
How about trying to see if you can get planning and such to operate an off license as well and sell booze and cigs?
How about speaking to other local business to offer mutually beneficial offers such as takeaways such as discounts on pizza when renting so many dvds or vice versa.
How about offering older films and such for sale if that's possible, have seen stores do that before.
Discount and loyalty schemes are good idea.