Corvillus

In addition to Half-Life 2 Episode 2 itself and Team Fortress 2, the Half-Life 2 Episode 2 bundle will also include an innovative puzzle mod called “Portal”. Basically, the idea is that you attempt to get through levels using a portal gun to teleport around obstacles. Sounds pretty simple, and it is, but the execution is amazing, as seen in this trailer.

YouTube - Portal Trailer [via Viper007Bond.com]