One Night:
One Night is a thrilling survival horror mystery which tasks players with finding a way to escape from an abandoned research facility where things have gone horribly wrong. It's up to you to unravel the secrets of 'The Complex' - a place long ago forsaken by humanity and beset by a horrible fate. As the seemingly lone survivor of this catastrophe, you'll need wits, reflexes and an itchy trigger finger to find your way to safety!
One Night was named as a freeware game pick (along with its sequels) on IndieGames.com, a subsidiary of Gamasutra, and was also selected as a featured game for Halloween 2011 on the official RPG Maker website.
You can see video of game play HERE however it's a video of the third in the series Full circle as i couldn't find one for the first game. It gives you a good idea as to how the game plays. :)
Download:
You can get One Night for free from Desura HERE or from the developers site.
The developer has also released two more free games in this series, One night 2: The Beyond and One Night: Full Circle with plans to release two more in the series. You can find these HERE. I will post them separately sometime soon. :)