It's not easy getting any movie made these days, but making an ambitious R-rated sci-fi movie that isn't based on a previous property, like "Looper" for example, is damn near impossible.

When director Rian Johnson finished the screenplay for "Looper," he created a proof of concept trailer that would help explain the look and feel of the movie and prove that it could be marketable to the producers who could someday fund the movie.

That trailer made its way online last week and should be interesting to anyone who saw and enjoyed "Looper."

You can check out the trailer and read Johnson's explanation of it after the jump!

The proof of concept video slices together footage from other movies like "Seven" and "Blade Runner" and features a voiceover from Joseph Gordon-Levitt.

This is a strange curiosity I thought might be interesting - just after I finished the script for Looper but before we began preproduction I asked Joe to record some voice-over, and with help from my friend Ronen Verbit constructed this "fake trailer" using clips from other movies. This is a fairly common thing to do when you're trying to get a movie off the ground, but it was the first time I tried it. It was meant to show more some of the film's tone, and to show how the odd concept could be presented in a clear and compelling way in the marketing. Zach Johnson did the sketches. Note that we hadn't begun the casting process yet, and the clips were chosen just based on their visuals and not by who is in them. - R. Johnson

"Looper" is in theaters now, and you should go see it.

What did you think of the early "Looper" trailer? Let us know in the comments below and on Twitter!