Chapter Select - Out of Bounds

West side - ground
This entrance is known to work on PS3. https://www.youtube.com/watch?v=ICDRW4rNGd8&list=PLKh97ggSLvdwwoKOTmJxPtCssIQP8KDGQ

West side - air
This entrance is known to work on PS4 and PC. https://youtu.be/70N9n1u71Nk?list=PLKh97ggSLvdwwoKOTmJxPtCssIQP8KDGQ

With this entrance, the idea is to gain enough speed to punch through the wall before leveling out. Try not not to level yourself out too soon, however, or else you might lose some of your speed.

A good height to aim for is about two times the height of the taller west building, or higher. Aiming higher seems to be better than aiming lower.

When pumping, make sure to save the third flap for right before you hit the windwall - too soon and you might not be able to punch through.

East side
This entrance is known to work on PS3, PS4, and PC. https://youtu.be/tfp66a0IeyM

Unused Hub Room
If you look below the southeast corner of the map, you can find a copy of the rooms used for choosing a level, only without a teleport circle or any Murals.

https://youtu.be/zUzNtEWtbLI?list=PLKh97ggSLvdzopSlCiZOJoXH4WwaILCy8