ZSNES is an SNES emulator written in x86 assembly. It was originally made in 1997, and has not been updated since 2007. It is currently one of the most popular SNES emulators.
- Compatibility is lower than any modern emulator due to low accuracy to real SNES system.
- Games crashing - Der Langrisser (freezes after 2-3 hours), Super Mario RPG (freezes in many different points of the game), Star Ocean and many other games have freezing and crashing issues.
- Bad sound emulation - A ton of games sound terrible on ZSNES; Earthworm Jim 2 has no sound effects.
- Super FX not clocked correctly - Star Fox runs twice as fast as it should.
- Transparency - Kirby Dreamland 3, Mecarobot Golf, Jurassic Park and any game that uses pseudo hi-res translucency won't display correctly.
Many ROM hacks and ROM hacking tools were made using ZSNES as a testing platform because of its popularity. However, because of the inaccuracies of the emulator, these tools and hacks are broken on other, more accurate emulators and real hardware.
In 2011, byuu released bZSNES - a modification of his bsnes that includes the optional inaccuracies of ZSNES and a similar GUI. This version of bsnes can accurately emulate the ROM hacks made specifically for ZSNES, which means the only thing ZSNES had going for it can now be played on a much more accurate emulator.
In 2013, a program by the name of ZMZ was released, which is a program that utilises libretro versions of Snes9x and the Next variant, as well as the Bsnes cores, much like RetroArch. The difference to RetroArch, however, is that it uses the exact same interface that ZSNES uses, making ZSNES effectively obsolete (moreso than it was already).