I’m genuinely excited about this movie. Both are absolutely fantastic actors and the plot seems downright amazing. IMDb offers this:
A killer who works for the mob of the future recognizes one of his targets as his future self.
So we know its going to be about Time Travel and some possibly Die Hard worthy action. Excitement level increasing!
Also, the poster is extremely well made. Its illustrations like these that make me want to be a graphic designer.
IMDb also has two other pictures of Joseph Gordon-Levitt in character. One of them with him brandishing a gun:
Edit: Looks like the trailer is here as well! IT LOOKS INCREDIBLE! Excitement level of the charts now!