5. The Stanley Parable
You wouldn't think setting a game in an office space would be damn-near lovable, but such is the most basic way of describing Galactic Café's Hobbit-like adventure about the titular Stanley, and his exploration of the facility around him. Although nothing herein is as overtly 'sci-fi' feeling as other entries on the list, it's the nature of what the facility is, the trappings of having an ever-present narrator dictating your every move and the myriad of endings that run the gamut from escaping in one piece to delving into lots of Orwellian tropes on the nature of worker-drones that create one hell of an atmosphere. All this might sound as though Stanley's journey is a downtrodden one - it's not, as sure there are some brilliantly socio-philosophical ramblings about the nature of choice, how gamers play things and how we interact with the world around around us both digitally and in real life, but it's a game built to be poked and prodded at from all angles, and you'll find something new every time.