Producks left us with a treasure trove of knowledge when he departed the community. This included two tutorials for Any%, also known as Wrong Warp and Credits Glitch.

Video guide for easy setup

This guide for shell placement in the easy setup created by 10ooki:

10ooki placement shot

Text guide for advanced setup.

Intermediate/Advanced Wrong Warp Setups Tutorial (Czikubi)

Any% guide (Kirua)

Any% tutorial by Poo (GrandPOOBear)

Any% guide (Producks)

Retro Game Mechanics in depth explanation (Dotsarecool)