Portal: Outside Influence

Portal: Outside Influence is a commercial Portal modification, containing elements from Half-Life and System Shock. It will be released on Steam and makes use of a custom build of the Source Engine.

The mod includes new testing elements, environments, music and voice lines. The mod has been designed by Sam Morris, who also designed the Portal map Portal: Skyline.

The music has been composed by several composers like NxSG, Alphadeus and Egill And. The story was written by Sam Morris and Emilia Wake.