Super Meat Boy has just been updated with new achievements, and though they are listed on the steam achievements page, they have no accompanying text on how to unlock them.\
The original secret achievements, the so-called cryptic, glitched achievements have already been identified elsewhere on this site.
Some, such as the "Rare, Medium, Medium Well, and Well Done" achievements seem similar to the "Medium Rare" achievement (added for the steam summer camp event).
Others, such as the "Well look at you!", "Seneca Falls", and the "Suffragette" achievement also have no unlock text, and they do not appear to be similar to existing achievements, either.
What do I have to do to earn these achievements?
Best Answer
The update notes say:
Since they are along the same lines as the previous achievement, they mean the player should complete both the light world and the dark world of a chapter, and the sum of the best times for that chapter should be lower than some threshold. Here are the descriptions of each one:
About the old secret achievements:
petaphile
code to play with Tofu BoySources:
Note about the times for the achievements: Many people use Super Meat Boy Stats (old repo at Google Code, new repo at GitHub) program to find out how much time they have spent on each chapter. However, the reported total time is not exactly accurate because "it counts 15 secs per completed warp zone", and people posting their total times didn't mention if the warp zone time has been subtracted or not. For this reason, the times I posted above might be quite inaccurate.