What was the hardest ability to put in the game?
From a tech perspective, I think the hardest might have been Echo. Her ability to duplicate an opposing hero brought a ton of challenges and bugs. In most areas of Overwatch, our ideas for what we would like to do are ever expanding in complexity. But we need to make it work with assumptions that we made years ago. Sometimes they don't mesh well. With Echo, it was a difficult clash to work out. In the end, she turned out to be a really fun hero, so it was worth the work. But there was a lot of engineering grey hairs generated around that one!