This is a complete rom hack of Wario Land 4 that I've worked on January 2020 - August 2021.
Teaser video: https://www.youtube.com/watch?v=mHB36wUjz4Q
You can find info about WL4 hacking at Wario Land 4 Hack Vault.
https://github.com/becored/WL4_PW/releases/tag/v1.0
Download "Wario_Land_4_Parallel_World_ver1.03.zip" from Assets.
I'm able to hack the game thanks to WL4Editor, very useful and user-friendly tool
Huge appreciation for tool authors and Wario Land 4 hack community!