Hi, Jordon. Have you considered how much this whole project is going to cost to get off the ground? Ok, you might be able to buy the place at a bargain rate, but that other 25% that isn't completed yet isn't going to come at a bargain rate. It won't be 25% of your purchase price. It will be more like 50% of what the place really would cost to build if you started from scratch. If it is just a shell, then you probably are still looking at installing some plumbing, electrical, heat & air, fire sprinkler system, floor coverings, wall coverings, restroom stalls, security system, parking lot, concession counters, concession equipment, seats, screens, sound, projection, etc. If somebody walked away at a certain point during construction, you can bet there was a long way to go before it was complete and not just a little bit. None of the things I listed are what I would consider cheap.
You don't want to go into this kind of expense thinking you are going to show movies from DVD or BluRay all the time. Why spend hundreds of thousands of dollars on a building and then comparative pennies on your projection system. People come to see the movies and don't care if your building looks nice if the picture and sound doesn't.
As quickly as the full digital conversion of the industry will be complete, you should really research professional cinema grade DCI compliant digital projection equipment to see how much it will cost. As Revrobor mentioned it will start at $50,000 per screen if you are lucky, and could be significantly more. You might be able to get by with film projection for a short time, but it won't be long until it will be completely obsolete. Probably by the time you could get your building completed, it may already be gone. I'm assuming your project won't be finished for at least a year.
To sum it all up, it's going to cost you way more than you probably realize to get this thing going. If you make it that far, you want to make sure that "second run" is a viable option. Will people wait to see a movie at your theater if there is a 14 screen showing films on opening day only 5 miles away? No matter how low you make your prices, many people just won't wait on you. You need to find a way to estimate how much business you will get. And, no, I have no idea how to estimate what percentage of the market goes to 2nd run theaters. But since most revenue from movies comes in early weeks, it seems to mean that people generally prefer early dates over later savings. There are some successful 2nd run theaters, but many more succesful 1st run.