Beyonce has made a massive regression to places unseen before. 4 was easily her best effort to date, it was her first album that combined rich vocals, with rich music. But Bow Down does not continue down that lane.
Her vocals, are confident and growling, nobody is going to stay standing when she commands "Bow down B****es."And those operatic vocals are stunning (haters beware). This makes the first half of the song bearable. However, the production and the deep rap vocals in the 2nd half are not doing her any favors. The production sounds like it was made on a 1990 Game Boy, and the deep vocals sound more demonically possessed than anything else. The song just turns into a hot mess, all too quickly.
Beyonce, please, I'm begging of you, if this is the style you have chosen for your 5th album, go back into the studio, and do it over. This is not the path for you, or for anyone.