Originally two separate entries into TF2Maps.net's 2010 art contest, winning both 1st and 3rd place.
Coldfront is a snow-themed multiplayer level I built for Team Fortress 2. It features 5 marked Control Points arranged linearly and symmetrically. To win, either of the two teams need to capture all five control points. Owning a Control Point would give benefits such as shorter respawn time, and often allowed you to spawn closer to the enemy HQ.
It was around April of 2010 when Valve asked me if they could include Coldfront in the next big TF2 content update. Coldfront was nearly 'completed' in my eyes at the time, so I took the next few months polishing and testing until it was officially integrated with the game in July 2010 as a part of the Engineer Update.
Development Timelapse Video:
http://youtu.be/voQuywKfjLI