Super Mario Bros. 4: The Undiscovered Zones (SMB1 Hack, by Szemigi) - Full Walkthrough

Hack by Szemigi, released in 2017.

https://www.romhacking.net/hacks/3658/

The followup to SMB3 TFW (NES). Here, Szemigi definitely tried to be more creative with various features and other gimmicks, we're in a completely different, exotic kingdom, going after Blower, Bowser's brother.

The level design is more of the same - oftentimes very World 9-esque. But overall pretty pleasant and not unfair. It is a challenge though, especially with the red Hammer Brothers and these black Piranha Plants that constantly pop out of the pipes. There are 6 main worlds and a World 7 that's unlocked once you pass the main campaign.

My only complaint is that the level design is even more messy at times than in the prequel, in particular the coin rooms are very nuts. I also faced some softlocks, in 1-2 and 2-1 in particular if I remember correctly. But hey, for a second hack, awesome!