Gate Online, a South Korean online game Kotaku previously introduced, appears to take its cues from two Valve titles: Portal and Team Fortress 2.
Team Fortress 2 is a well-spring of sorts. Last summer, the game inspired another South Korean developed PC title, H.A.V.E. Online.
The influences for Gate Online are not as blatant as for H.A.V.E. Online, and the game's developers do seem like they are trying to incorporate those influences and push them forward in a somewhat engaging way.
Thanks Joshua for the tip!