Under what circumstances can I unlock the negative levels in Super Meat Boy?

While playing one of the dark world stages in Level 1 of Super Meat Boy, I reached the end of the stage after dying several times. However, Band-Aid Girl, instead of doing her normal crying animation, was messed up in appearance: glitchy and spinning around. Though I initially hesitated, I brought myself to touch her and complete the level, only to find myself in World -1. This stage was quite difficult and featured arcade-style play with only three lives as with the world zones. When I got game over and went back to the map screen, this stage was now accessible as a stage before the first stage of the Forest light world stages.

I managed to unlock the same sort of stage in the Salt Factory world.

I'm guessing that there are six of these, one for each of the normal worlds as well as the secret world. But I'm still not sure as to how I go about unlocking them.

Under what circumstances does Band-Aid Girl become glitched up, allowing me to unlock the negative levels? Is it determined by chance or do I have to die/not die a certain number of times to get her to become glitchy? Does this only occur on certain levels?

Solution 1:

Bandage girl has a random chance to glitch every time you spawn on a level. She can glitch in any level from 1 to 20 for each of the worlds 1 to 6, whether you're in the light or dark half of a world. There is exactly one negative level for every world.

To unlock level -1 for a world, pick a level in the world that is short and relatively easy. Below are good examples (in the light world) including a recommended character:

• 1-3 (The Gap) using anyone
• 2-10 (Johnny's Cage) using Jill (if you don't have Jill, see this video)
• 3-6 (The Shaft) using anyone
• 4-6 (Leviathan) using anyone
• 5-10 (Grinding Mill) using anyone
• 6-2 (Schism) using anyone

Then:

1. Look at or get to bandage girl and see if she is glitching. She will be spinning and making a distinctive pinging sound. I recommended levels where you can (mostly) see her from spawn.
2. If she is glitching then touch her to unlock level -1. Otherwise, kill yourself, respawn, and go back to step 1.
3. To play the level you just unlocked, go the light half of the world you unlocked it in. It will be available to play as a yellow-colored level beside level 1.

Solution 2:

If you continuously die, Band-Aid Girl should eventually become glitched. While she is glitched, standing next to her should teleport you to the negative level. And you are correct, there are negative levels for Worlds 1 - 6.

Here is a video of somebody unlocking the first negative level.