Since the other posts are kind of old, if you need to unlock this achievement but have no one in your friendlist with it, send me a request and I'll add you. I just recently unlocked this achievement and I know how frustrating this can be (especially if you're trying to 100% the game)....

---------- Edit: WE FOUND THE PROBLEM! The game won't load the leaderboard if you have over 100 friends! Just go to your friends page, select "Manage Friends", select all, and uncheck a friend who has played the game. Then Block everyone else. It's not

I did it, it was hard, I tried not to use guides since I thought it would be cheap way. I actually liked the challenge but I really feel that CH2 should have two checkpoints after sewers.

See screenshot http://gtm.you1.cn/sharedfiles/filedetails/?id=106414484 I think this another bugged script, helicopter just kills me through wood planks