Stella is a multi-platform Atari 2600 VCS emulator released under the GNU General Public License. Now you can enjoy all of your favorite Atari 2600 games on your Mac thanks to Stella!

Stella allows you to enjoy all of your favorite 2600 games once again by emulating the 2600's hardware with software.

Features:

• High speed emulation using optimized C++ code
• Supports high quality sound emulation using code derived from Ron Fries' TIA Sound Emulation library, including stereo sound support
• Emulates the Atari 2600 Joystick Controllers using your computer's keyboard or joysticks
• Emulates the Atari 2600 Keyboard Controllers using your computer's keyboard
• Emulates the Atari 2600 Paddle Controllers using your computer's mouse, keyboard or joysticks
• Emulates the Atari 2600 Driving Controllers using your computer's keyboard or joysticks
• Emulates the CBS BoosterGrip Controller using your computer's keyboard or joysticks
• Emulates the Sega Genesis Controller using your computer's keyboard or joysticks
• Emulates CX-22 / CX-80 style trackballs and Amiga Mouse using your computer's mouse
• Support for real Atari 2600 controllers using the Stelladaptor and 2600-adaptor
• Support for the speech portion of a real AtariVox device connected to your PC using a USB adaptor
• Supports EEPROM emulation for AtariVox and SaveKey controllers
• Supports all known bankswitching schemes (let us know if there's one we missed)
• Supports cartridge autodetection for almost all bankswitching schemes
• Supports Supercharger single-load and multi-load games
• Supports ROMs stored in ZIP and GZIP format, as well as the usual A26/BIN/ROM formats
• Supports property file for setting the properties associated with games
• Supports the NTSC, PAL and SECAM television standards in 50Hz and 60Hz mode
• Supports autodetection of display format for 50Hz vs. 60Hz modes
• Supports several "undocumented features" of the TIA graphics chip used by some games
• TIA emulation supports full collision checking, with ability to disable both TIA sprites and collisions for each object separately
• Built-in extensive debugger, including the Distella disassembler
• Emulation of CRT TV systems with OpenGL shaders, including texturing, colour bleed, RF noise, and phosphor burn-off
• Built-in ROM database with information compiled by RomHunter

Requirements:
OS X 10.7+
64-bit Intel