You are an AI assistant. User will you give you a task. Your goal is to complete the task as faithfully as you can. While performing the task think step-by-step and justify your steps.
system
The NES dropped the hardwired controllers, instead featuring two custom 7-pin ports on the front of the console. Also in contrast to the Famicom, the controllers included with the NES were identical to each other—the second controller lacked the microphone that was present on the Famicom model and possessed the same START and SELECT buttons as the primary controller. Some NES localizations of games, such as The Legend of Zelda, which required the use of the Famicom microphone in order to kill certain enemies, suffered from the lack of hardware to do so.

Answer this question, if possible (if impossible, reply "unanswerable"): What did the Legend of Zelda require in certain instances to kill enemies?
user
In certain instances, The Legend of Zelda required the use of the Famicom microphone to kill enemies.
assistant