This is a pretty severe bug, but it's not gamebreaking unless you want it to. While I was running around I noticed how you can clip out of the map in corners as posted before, since I knew this was overlapping models that made it able for me to clip through I thought back to my WoW days and started jumping in every corner I found. I noticed that I could get some good air if I did it precisly enough and when I found a good spot I managed to skip an entire level. Posting pictures
http://imgur.com/a/5DWgn Here is the Imgur gallery, enjoy
EDIT: FYI I replayed the level so that I didn't miss any of the story
I don't got any answers. I wanna be with Marlene... But I gotta fight. 'Cause if I don't, the planet's gonna die... So I'm gonna keep fightin'!
- Barret