SFX does a very good job of presenting the user with a useable interface. The Lynx's controls are used in a very intuitive way to adjust all aspects of the Lynx's registers. You can play noises as you adjust them to see how they are changing or only when you reach the exact registers you want.
Unfortunately, SFX has some flaws that will keep it out of mainstream use. The user is not allowed to string together noises to create a song and therefore tends to SFX grow boring if you are not attempting to use it to create sounds for a purpose. Truthfully, if the registers were explained more thoroughly to the user, the cartridge would be a very interesting lesson in how computer games work. Since they aren't, the cartridge is more of a trial and error lesson in figuring out how the registers work. If you catch on to what's going on, you'll be one step closer to understanding the Lynx and programming in general. Not a bad deal for those of us that are curious about how everything works.
That having been said, if you consider the fact that SFX will only
attract programmers and the curious it is sure to become one of the rarest and
most collectable Lynx cartridges. Since SFX was only manufactured in
limited quantities and was Songbird Productions first release, if you want what
will surely go down as a historic Lynx release as well as a collectors item snag
this one before it's gone.