David Cross, the actor who voiced Zero in the game, said that he hated the mission "Supply Lines", which his character was in, because of how difficult it was and finding his voice accompanied with it to be annoying.

In an interview, Cross said, "It's the most annoying voice you could imagine, accompanying that," "I stopped, I tried to cheat, I could not listen to myself, it was so annoying," "So annoying. I hated it. And I couldn't fucking do it. The RC thing? ... It's impossible."