The entrance to the secret level is located in chapter 26 (the one with the huge fly on the level preview). Instead of proceeding to the right as normal just go down the long ladder on the left. When you reach the bottom go right into the darkness until it seems to be a dead end, but it's not, it's just a ledge that blocks your way. Jump and proceed to the right until you come to a clearing with candles around (the one you can see on the icon of this guide) and you're right in front of the entrance to the secret level and a very special challenge.

You may have been down there already in your first playthrough but the door was locked. To open the door you have to collect the 10 hidden eggs (light dots which crack when you run over them) in the game first. However that's no big deal as you can jump to each chapter after your first playthrough. If you have problems finding all eggs, I've made another guide showing all locations and how to get there, some of them are quite tricky.

http://steamproxy.net/sharedfiles/filedetails/?id=113719610
I've also come over some rumors on the internet, that it requires you to beat the game in one sitting with less than 5 deaths but that's just wrong, you only get the "No Point in Dying" achievement for doing so and it has nothing to do with the secret level.

First I recommened this level only to players who like the challenge and can live with trial and error and don't rage too quickly. As you can hardly see anything it requires you to listen (stereo speakers or headphones recommended) and watch carefully to determine what obastacle is in front of you.

However all the obstacles that appear in the secret level have also been part of the normal game. So the challenge is to remember which one it is, figure out the layout and find a way through it. This requires not only logical reasoning but also good timing.

The exit of the secret level is in level 34, although I wouldn't call it a shortcut.

You're rewarded with the secret Ding! achievement for completing the level.

Note: There's also a german version of this guide available on another site, with the same structure and content. I'm the author of both, I just translated it for the steam version into english.

Version History

• 2013-07-08: Edited description on how to unlock the level
  
• 2012-12-15: Submitted first version of the guide