State of NES Emulation
In 1983 the world of console gaming changed with the introduction of the Family Computer from Nintendo. The Famicom (Family Computer) didn't find its way to North America, Europe, and Australia until 1985 as the Nintendo Entertainment System (NES); and singlehandedly ended the video game dark ages. Today the Nintendo Entertainment System still ranks in the top ten of best-selling video game systems, and is by far the most emulated video game system.
Nintendo standardized the practice of producing the hardware and a small collection of software for their system, while licensing third-party developers to also produce games. This gave the NES a huge software collection, launching the franchises of Super Mario Bros., The Legend of Zelda, Metroid, Mega Man, Castlevania, Final Fantasy, and Dragon Quest. Individual classics include Duck Hunt, Golf, Teenage Mutant Ninja Turtles, Baseball, Tetris, and Excitebike.
Luckily for all of us, the NES has been near-perfectly emulated on the Mac for years. Richard Bannister's port of Nestopia has been maintained to match progress done on the official project. Nestopia includes cycle-exact emulation which means that the emulator accurately emulates the timing of the actual hardware. This is crucial for classic systems such as the NES where developers drove the player to use precise timing throughout their games. Richard Bannister's Nestopia also provides support for the Nintendo Zapper, a light-detecting gun used for games such as Duck Hunt and Hogan's Alley.
Nestopia's only short-coming is the need for a 600MHz or higher machine. Today this is not much of a problem, but if you're interested in digging up an old Mac to use as a classic gaming setup, you might find it to be a little slow. The are a handful of options for someone in this position. MacFCEU is an open source Mac port of the popular FCEU emulator, but MacFCEU lacks the polish you'll find with Bannister's emulators.
Assuming you're using a relatively new Mac, you have access to a lot of different options when it comes to controls. The most basic is obviously using the keyboard, and for exploring old NES games this might be the best approach. Unfortunately two-player becomes nearly impossible (or at least uncomfortable). Most popular emulators provide support for USB controllers, and hundreds of these can be found on Amazon. I can recommend the Logitech Cordless Rumblepad 2 .
If you have a Nintendo Wii, there is a far more clever way to get classic controllers for emulators. Using DarwiinRemote you can use your Mac's built-in bluetooth to connect a Wiimote and with some simple configuration, play NES games using your Wiimote.