This movie looks interesting but I'm coming in in the middle of the picture(so to speak ) Is this based on th same Midnight that was the background for a Rune Bound Expansion?

OD

In short, yes.

In long, Midnight is a Roleplaying game published under the OGL.  It had some rules particular to it, but was primarily a setting in which to play Dungeons and Dragons and requires use of the 3.5 D&D rulebook (according to the back cover of the Midnight 2nd edition book).

The Runebound expansion featuring the Midnight setting is more or less a Runebound expansion using a theme similar to the Midnight RPG setting.  I do not own the Runebound Midnight expansion (but would love to get it if they ever publish it again.)

Indeed as Ludyee has confirmed it is the same. I prefer to give a slightly longer answer specifically regards the RPG

Yes released under 3.5 OGL Midnight 2nd edition was released. Support continued until 2007. A gritty campaign, more so than the Forgotten Realms, Eberron etc (interestingly Wizards are to re-release Dark Sun which was a gritty setting) so I guess depends on what style of game you want to play. Very well written with good atmosphere. The world is fleshed out really well. You only get a snapshot of that in the film. There is a wealth of material that could be mined if they get to make more films or a TV series.