The character select screen alone has four layered versions that build on each other. Newer Super Mario Bros. Wii is probably the most well-known Mario ROM hack, and its original soundtrack is a big reason why. "Airship" absolutely slaps with this driving military march energy that feels more intense than anything in the official games.
Read more
"Ambush" brings genuine tension, which is wild for a Mario game. The forest and jungle themes nail that organic, leafy warmth while the castle tracks go appropriately dark and urgent. Every single track has a fast variant for when the timer drops.
That level of attention to detail in a fan project is honestly staggering. If you've played any Mario mod, start with this one and its soundtrack.