Update [Tue 19th Dec, 2023 12:15 GMT]: It seems another game is now being added to the mix! Yesterday, the ROM hacker Kandowontu shared an incredible look at an upcoming update to Celeste Mario's Zap & Dash from developer w7n that will introduce Baba Is You-style mechanics to the well-received hack.

In case you're unaware, Baba Is You is an indie game from the Finnish-based developer Hempuli that was released in 2019 and focuses on solving puzzles by moving around blocks to change the rules of the world.
You can see a little of how this will work in the context of a Super Mario Bros hack below:

Original Story [Thu 6th Jul, 2023 12:30 BST]: One of the greatest things about romhacks is that, due to their totally unofficial nature, they can get away with doing some fun stuff โ€“ like mixing two different games to create something completely fresh.

That's certainly the case with Celeste Mario's Zap & Dash!, a Super Mario Bros. romhack which infuses the traditional Mario experience with a Celeste-style challenge.

The levels in this "hastily done minihack" are the result of just two months of design work, which makes it even more impressive.

w7n is responsible for the programming, levels and music on this one, with Morshu contributing the main graphics. StudsX made the bonus levels and karmic supplied the music engine code. Finally, Eden GT created the game's title screen.

[source romhacking.net, via twitter.com]