The original plan was to make The Sacrifice for Left 4 Dead only. L4D2 had The Passing, and its counterpart was meant as an exclusive for the original game. Chet explains. “It’s a really fun campaign, it’s got lots of high Hunter leap points and stuff. And we said ‘You know, this would be really cool in Left 4 Dead 2. Some of these locations would be cool for the Spitter and the Charger.’ So we decided we’d release The Sacrifice not just for Left 4 Dead 1, but for Left 4 Dead 2.”
The decision to add No Mercy to Left 4 Dead 2 was simply that it was very popular with players, and Valve like it a lot. “When we first changed them over,” Chet says, “they were brutally hard. Your strategy of holing up in corners just disappears, because the Spitter is going to wreak havoc. The Rooftop of No Mercy now, with Chargers and Tanks, is… you’d better not stand by a ledge.”
They addressed that by giving players the best of Left 4 Dead 2’s arsenal, including several of the mighty M60 machineguns added by The Passing. “You’re playing as the Left 4 Dead 1 characters in Left 4 Dead 1 maps, but you get melee weapons, the new weapons, the defib – all the stuff from Left 4 Dead 2. You get to see Zoe with a chainsaw, Zoe with an axe,” Chet says with ill-hidden lust.
It looks like the upcoming Left 4 Dead DLC, named The Sacrifice, has something for owners of both games, then. You can read the rest of the interview at PC Gamer's website.
What makes this any different than if they had just packaged the L4D1 content with L4D2 from the get go? Nothing... Literally, nothing...
