After the last couple days of dispute between anonymous Gearbox and TimeGate employees on Reddit, we have a quote that settles the capacity that the two companies worked under on Aliens: Colonial Marines.
"Whereas in a traditional co-dev situations, everyone gets a specific thing to work on; TimeGate and Gearbox do everything horizontally," Robert Siwiak, TimeGate’s VP of business operations said at a Houston IGDA event on August 22.
Horizontal development means each section was created through back-and-forth development with Gearbox. They were not outsourced to develop a particular part of the game, as several Gearbox employees claim.
I can also confirm, through my source, that the Reddit comments are coming from actual TimeGate employees.
This information comes from Houston reporter John-Henry Perera who interviewed Siwiak and tweeted the above quote.