The news was announced over the weekend and perhaps more excitingly also came with the reveal of an alternative version featuring a SNES-based custom level editor named Super Mario Bros. Maker, which will enable players to edit the game's levels.
In order to edit levels, players simply have to press X when they start a new game and they will then be able to select, copy, or paste any 16x16 block that appears at the top of the screen with either an SNES controller in port 1, or an SNES mouse in port 2.
According to Infidelity, in the file's README, the idea dates back to 2019/2020 and was initially envisioned as a ROM hack for the NES, but was put aside when he "started to lose confidence in it". From July to August of this year, however, he started looking into the possibility of incorporating the editor into a future release, eventually managing to put together a BETA as he assembled his latest NES to SNES port.
The level editor currently doesn't have the option to edit enemy sprites, as outlined in the notes, but the feature is planned to be incorporated in a later build.
You can download the NES to SNES port or the custom editor now from the Internet Archive.