Reviews of the new songs from Mark Ronson and Fifth Harmony

By Kyle Anderson
November 21, 2014 at 05:00 AM EST

Mark Ronson feat. Bruno Mars, ”Uptown Funk”
For his next throwback trick, Mars channels a Purple Rain-era Morris Day over a guttural workout laid down by expert nostalgist Ronson. It crackles just enough to keep out the chill after a dip in Lake Minnetonka. B

Fifth Harmony, ”Sledgehammer”
The ladies reveal, ”If you take my pulse right now/It would feel just like a sledgehammer.” If that troublesome heart rate is the secret to creating club-ready delights like this, may they never get that checked out. B+