To get this achievement you HAVE to play the game on expert. Any other difficulty will not suffice. All you have to do is play through the game like normal and once you get past the part where you have to collect flowers and crystals you will encounter the survivor. Right after you cut down the spider web, the next screen will show the "survivor" popping up and down in the left hand background, if this doesn't happen for you then you aren't on the right difficulty setting. Once you complete the collection of flowers and crystals just move forward and once you take the left hand path and end up on a screen that has what looks like a train car in the background you will see the achievement pop. There is nothing special to get this achievement besides the difficulty, you can still use hints and such without disqualifying yourself.