Well guys, Half Life 3 confirmed.

[2D Brain]

Valve was making Half Life 2 Episode 3 and created an interesting game mechanic that they felt was more exciting to pursue and explore in an unrestrained context, and that became Portal. Portal 2 is actually Half-Life 3 and I'm glad Valve went that route. Perfectly executed game concepts, mechanics and inspired game design etc > obligatory names, numbers and fan service.