i believe they run on a newer version of the source engine. we are limited to games that are on the steampipe branch (orange box release) those are hl1s css tf2 hl2 day of defeat source and some other games. now L4D1 and 2 might work on top of portal 2 but i dont think any1 has tried modding it yet.
What are they going to do next? Mount Left 4 Dead 1 and 2?
i believe they run on a newer version of the source engine. we are limited to games that are on the steampipe branch (orange box release) those are hl1s css tf2 hl2 day of defeat source and some other games. now L4D1 and 2 might work on top of portal 2 but i dont think any1 has tried modding it yet.
So you still can mount Episode 2?
im not sure how well it would run considering hl2 has stutters occasionally but theoretically you could.