Citra is a work-in-progress 3DS emulator. Citra can currently emulate, with varying degrees of success, a wide variety of different homebrew programs and commercial software...
Citra can, ostensibly, "play" many different games, including The Legend of Zelda: Ocarina of Time, and Animal Crossing. Many games, however, will not load at all, only showing a black screen. Many other games will only show the title screen and then freeze, or crash.
You can expect many games to run slowly, though, and to exhibit many gameplay and graphical glitches.
If you're interested in 3DS emulation as an experiment, you may gain something out of trying Citra, but if you're simply looking to play games then stick to your 3DS handheld.