JoeKarlosi’s review published on Letterboxd :
After ABBOTT & COSTELLO MEET FRANKENSTEIN this is my next favorite of their "meet the monsters" movies. Thankfully it offers an added treat by starring horror legend Boris Karloff in the part of Dr. Jekyll, though when he's running around London as Mr. Hyde it is actually a stunt man in a monster mask.
Bud and Lou are "Slim" and "Tubby" (okay, so the names aren't very original), two Americans who are hired as bumbling police bobbies in England. It isn't long before they're thrown off the force for their incompetence, but they have a plan to try and get their jobs back by trying to apprehend the "monster" that's been loose and murdering people. This would be Mr. Hyde, the savage alter ego of Dr. Jekyll (Karloff).
As portrayed in this film, Jekyll is not very innocent himself, as he is rather a schemer who is madly in love with his young ward (Helen Westcott) who is young enough to be his own granddaughter! The comedy of Abbott and Costello this time relies more on slapstick gags than their trademark verbal "routines". Both comedians look like they did during their television show, as this feature was produced at the same time. If you're a fan of Boris Karloff, this film puts him to far better use than he was given in 1949's ABBOTT AND COSTELLO MEET THE KILLER. It also works as a straight monster movie along with the jokes.