We're currently working on a new version of Dear Esther, responding to many of the comments made here (thanks to everyone for those). Key areas to change are:
1. Getting rid of those invisible walls
2. Making the pathways more obvious in the first two levels
3. Dealing with some texturing and displacement issues
4. Adding a few more cues in harder to reach places (you explored more than we thought you would)
5. Deadling with the double-cues on the west side
6. Extending the caves.
All the video footage of errors has been brilliant, thanks for all that.
Secondly, a few people have mailed through their interpretations of the story, which has been really interesting and brilliant to get. I'd love to get more of these, see how people have nailed it all together. It would really help us with the research ideas that sat behind the project. PM me your version of the plot - it'd be very appreciated (and I will eventually release my version). We may well use your contributions in a research paper, but I'll contact you directly for a permission in that case. Any questions, drop me a line.