MirrorMoon, by Team Focaccia / Santa Ragione

Run, don't walk, to your nearest electro-computer-device and play MirrorMoon. It was a Global Game Jam 2012 project / recent contestant at this last GDC's Experimental Gameplay Workshop, and stupid ol' me had never heard of it before then.

The FPS controls are somewhat non-standard, but it's for an important reason, and the deviation is handled pretty gracefully. Otherwise, the sounds, the colors, the scope of the level design -- everything is perfect. So so so perfect; part of the GGJ team included the man behind first person runner Fotonica, and it shows in the bold visual design. It's a really solid first person experience that'll improve your day.