Before Call of Duty: Advanced Warfare went into development at Sledgehammer Games, the studio had begun work on a third-person Call of Duty: Vietnam title for Activision, which would have focused on the “Secret War” in Cambodia and Laos.
In the June 2014 issue of Game Informer (via GameSpot), Sledgehammer Co-founders Michael Condrey and Glen Schofield revealed that Call of Duty: Vietnam started production after both of them left Visceral Games after working on Dead Space. However, development stopped after about 6 months as Sledgehammer was asked to help out Infinity Ward with Call of Duty: Modern Warfare 3, following Vince Zampella and Jason West being fired from Infinity Ward and taking some developers to Respawn to work on Titanfall.
Revealing how Sledgehammer was “going for some Dead Space moments” in Vietnam and large sections would take place in underground tunnels, Schofield explained how far they had gone with the game before scrapping it:
We had spent six or eight months on it, and were really getting into the story. We had some really cool mechanics. We had a big moment that I would love to get into a game someday, but it’s not something we could do in first-person.
In the end, 15 minutes of Vietnam were playable, and Schofield adds, “We would have loved to make that [third-person] game. It was in a space that we enjoyed, but how does anything compare to the first-person blockbuster release of 2011?”
[Image is from Advanced Warfare]