I skipped the introductory mission and can't restart it. Is this a bug? Can I still get the 'Beta.exe' background and 'Complex Study' emblem cosmetic rewards?

I died and skipped the introductory mission, and can't find a way to restart it.
Is there simply no feature to restart the introductory mission like in other games, or is my game bugged?. Can I still get the 'Beta.exe' background and 'Complex Study' emblem cosmetic rewards?