Zynga chief operating officer Clive Downie has resigned from the social gaming company and is joining Unity Technologies as chief marketing officer, GamesBeat has learned.

Downie, the No. 2 exec at Zynga, formally resigned and is now joining Unity, whose design engine and tools are some of the most used in the game industry. This move comes 15 days the company announced that after Don Mattrick, the chief executive of Zynga for 20 months, left and was replaced by founder Mark Pincus. Here’s the filing.

“We are thrilled to have Clive on board,” said John Riccitiello, the chief executive of San Francisco-based Unity Technologies, in an interview with GamesBeat.

The turnover isn’t a big surprise, but it won’t be good news for Zynga, which missed analyst targets in its last earnings period and reported a slight loss for 2014. Downie joined after Mattrick came on board, and he was the operational chief on mobile games. Zynga was the social gaming king on Facebook, but it’s struggled in the transition to smartphones and tablets. Downie’s job was to use his expertise — he was formerly the chief of the DeNA West division of Japan’s DeNA — to help Zynga figure out mobile.

Unity plans to use that experience to help Unity compete in a competitive game-engine market. It¬†recently launched the Unity 5 game engine — a multiplatform tech — but it’s battling with Epic Games’ Unreal Engine and a host of smaller companies¬†for marketshare.

“Clive and I go back a long ways,” Riccitiello said. “I’m super-happy to have him. He has a deep history in mobile gaming and a long history of marketing skills.”