You can take some physics assets from my demo that I made a little while ago: How can I make sonic go upside down without falling - #16 by Kiwiphoenix364
Mainly the slopes (loops and upside down physics wouldn’t fit well in Mario).
I have wall sliding physics from New Super Mario Bros Arcade (if you can find where exactly in the code it is because this code is cluttered) and a more refined version (yet harder to implement because it is specifically designed for an auto runner in Newer Super Mario Run Arcade).
Feel free to take these assets and implement them (if you want).
Also by BIG I meant if it gets more than one person collabing and like 3 revisions/updates, because I don’t (particularly) want to update a game that nobody cares about.