According to Gamasutra, Valve’s Doug Lombardi told them that Church had been with the company for “a couple (of) weeks,” though he was unsure what, if any, specific project the designer has been assigned to.
It’s an exciting prospect, either way. It’ll be fun to see what new ideas Church brings to Valve, who definitely have the funding to back projects that other major publishers would be reluctant to spend money on.
