ZSNES was one of the first Super Nintendo emulators that could play a wide range of games at good speeds, which once made it one of the most popular Super Nintendo emulators. Unfortunately, it has not been updated since 2007 and is now considered obsolete. As this emulator focuses on speed, its accuracy is low compared to other emulators. I recommend you pick a different emulator instead.
One particularly worrisome detail is that severe bugs have been found in ZSNES. These bugs allow for the execution of arbitrary code. Or to put that in more understandable language: a hacked ROM could use ZSNES to inject your PC with malware. So if you choose to continue to use ZSNES make sure you get your ROMs from verified sources. You can find more information about this issue on this Reddit thread.