In short: Cold, wet, and utterly brilliant In full: This was my first hell runner and I'm almost certain I'll be taking part again next year.
For the first 2 or 3 miles we had the chance to admire the views of the countryside while winding uphill on pretty even terrain. There was a queue right from the start (I was a few hundred from the front) and at times people were walking rather than jogging, but after a while the crowd thinned out and I had a chance to stretch my legs a bit.
After passing the start line again (and seeing eager Second-Wavers waiting to get going) I was wondering what all the fuss was about... but I had been lured into a false sense of security because from that point on things became gradually more gruelling. I can't remember at what point I thought "why am I doing this?", possibly scrambling up the hills of hell but most certainly by the time I reached the lake. This was the one aspect which I thought could actually be dangerous. I was one of the majority who stayed on the underwater ridge to keep the water at around waist height (for me anyway) and I must have been in there for at least 15 minutes, at times not moving at all. In short it was bloody freezing! After that my legs felt like they were packing in, but after a few minutes of jogging they warmed up again and my toes went from completely numb to feeling like I had a couple of radiators in my shoes before settling on mild throbbing.
The final bog of doom wouldn't be that challenging by itself but I was so knackered by the time I reached it it was as much as I could do to remain vertical. After limping around the last loop of the fun run track I managed a "sprint" finish, and had never been so happy in my life to be handed a milkshake.
My shoes are still in a bin bag and after 3 showers my feet have retained a brownish hue, but the sense of achievement has lingered. Overall it was very well organised. I agree with some of the other comments regarding safety in the lake. If anyone got into serious trouble they would have had help for sure, but that help would have come from a few dozen borderline-hypothermia cases rather than fresh and warm stewards. If they can sort that aspect out I think it'll be just about perfect. If such an ordeal can ever be called perfect.
For the record, 33 hours after finishing I'm still knackered! Date of review: November 4, 2012