Super Mario Bros. 3: Fight Hammer Bros Twice

In this video I explain the cause for a little known exploit that lets you fight a Hammer Bro twice. Unfortunately, due to it requiring the player to wait for 3 and a half minutes, it cannot be used to save time in a speedrun. To add a bit more detail, address $7973 is only set by the invisible object that manages pipe stages, and cleared by the normal map function. The only instance in the game’s code where it is used is to skip checking mario’s position to see if it overlaps any map objects. I assume this is to save CPU cycles, though perhaps this is to prevent an N-Card game that’s resting on a pipe from being completed if you enter from the other side? Wouldn’t it make more sense to toggle a bit when entering a stage through a map object, then check it after returning to the map? If it were me, I’d just store the index of the map object you enter, then there’s no need to run the expensive calculations where you check your position on the map and compare with every object’s positions. In any case, this lets you collect an item from a Hammer Bro twice, at the cost of the tedious setup required, as well as a little luck to ensure the Hammer Bro walks to your position. If a faster method of dying in a pipe level could be found, this could possibly save time by allowing you to get extra copies of Jugems Cloud, thus allowing you to skip more of the longer levels.