A single button that changes from "Open" to "Talk" or "Push" based on your surroundings. The Ocarina:

Nintendo actively protects its IP. Downloading copyrighted ROMs for games you don’t own is illegal in many jurisdictions. Even if Zelootd.z64 is a hack, distributing it without permission of the original hack author may violate their license.

Some ROM hacks are designed with specific challenge rules in mind, such as a "no sword" run, where the player must complete the game without using the sword, or a "reverse game" where the goal is to lose as quickly as possible.