Erik Wolpaw, who worked on both Half-Life episodes and Portal, is rumored to have returned to Valve after leaving back in 2017. Reddit user Trenchman noticed Erik Wolpaw’s name appears in the credits for Artifact. You can see his name appear in the credits below, which are listed alphabetically by first name.
Wolpaw’s contribution to Artifact is unclear. It’s possible his contribution could’ve been made before leaving the company, as the game came out on November 28, 2018, a little over a year after Wolpaw departed. Another explanation for Wolpaw’s appearance in these credits is that this was a one-off project for him and not necessarily an indication of permanent employment.
This same Redditor also provided a screenshot in which they emailed the president of Valve Corporation, Gabe Newell, to ask if Erik Wolpaw has returned. The response, within the screenshot, simply stated “He’s back.” The likelihood of Newell responding to a random email seems low but Valve News Network, a popular YouTube channel dedicated to keeping up with all things Valve, claims to have vetted the email.
The sender of the email confirming the return of Erik Wolpaw to Valve has given me the specfics to prove it’s legitimacy. He is back, holy shit. @Wolpaw
— Tyler McVicker (@ValveNewsNetwor) January 4, 2019
All of this remains a rumor until Wolpaw or Valve confirms it publicly, directly or by listing Wolpaw on the staff list.