Graphics are implemented using SDL. All instructions/features are implemented currently (it passes all tests) with the exception of the buzzer, and the clock speed also needs to be tuned.
Here is the emulator running pong:
Install sdl2 brew install sdl2. Just clone, run make, then ./emu [rom file]. The 4x4 keypad is mapped to the leftmost 4 keys on each row, and ESC exits the emulator.
To use the debugger, ncurses is required: sudo apt-get install libncurses5-dev libncursesw5-dev.
For a quick demo of the debugger, use make test.
Debugger in action:
For another means of graphical output, I've wired my Pi to a 128x64 SSD1306 oled display, with each of the 64x32 CHIP-8 pixels scaled up by 4.
I found Cowgod's Chip-8 Technical Reference to be highly useful in implementing this emulator.