One of the 3, 452 enhancements Meizu implemented is the "Smart Bar, " where Meizu has somehow merged the app's bottom menu bar and the system's virtual softkey bar for the sake of screen space and intuitiveness.
One SU (especially around the camera), but flip it around and you'll notice what appears to be a pair of front-facing stereo speakers (aka BoomSound as it's marketed as for the One), as well as the same dual softkey implementation on the company's latest flagship.