Super Bowl ad winners and losers

(CBS NEWS) -- The Super Bowl is a high-stakes game for advertisers, with dozens of brands spending $5 million each for 30 seconds of air time and relying on humor, emotion and shock to win over viewers. 

Advertisers shell out millions for a few seconds of airtime during the Super Bowl because it's one of the few events where viewers look forward to watching the ads. Even better, it regularly draws more than 100 million viewers, typically making it the most-watched broadcast of the year. 

This year, advertisers mostly played it safe, relying on humor and sentiment to get their brand messages across. Yet that doesn't mean there weren't losers during Sunday's game. 

A Ram truck ad that used an audio recording of Martin Luther King, Jr. delivering a speech drew considerable backlash, with viewers criticizing it for exploiting the late civil rights icon to sell trucks. The ad earned a "C" grade from the Kellogg School Super Bowl Advertising Review.

I don't care if MLK family authorized the Ram ad (they probably did) The ad was gross and exploitative.

— Oliver Willis (@owillis) February 5, 2018

Other ads that missed the mark include Squarespace and T-Mobile, with Kellogg professor Derek D. Rucker noting what he described as their "questionable positioning and unclear calls to action."

Amazon's ad -- called "Alexa Loses Her Voice" -- earned the top score from the USA Today Ad Meter as well as an "A" grade from the Kellogg School, which bases its score on marketing goals such as whether the commercials offer a strong link to the brand's message. 

I’m still laughing out loud at the @Amazon#Alexa ad. Funny all through but HILARIOUS when we got to Anthony Hopkins. ??? #BrandBowl52#SuperBowlLII

— Kirsten Jensen (@NextKirsten) February 5, 2018

Tide's series of advertisements also scored well, according to the Kellogg School. The commercial featured David Harbour, one of the stars of "Stranger Things," and a very meta-approach to advertising. The detergent, which had an ad in every quarter, posited that every ad with clean clothes could be a Tide ad. And its own ads pretended to be marketing another product -- like a car or beer -- before Harbour revealed that the spot was actually a detergent ad. 

Another winner was the NFL's "Touchdown Celebrations to Come," which featured Eli Manning, Odell Beckham Jr. and Landon Collins and a "Dirty Dancing" homage.

Below are the Kellogg School's grades, from 'A' to 'F', for ads that ran during Super Bowl 52.

A

Amazon
Mountain Dew
Doritos
Avocados from Mexico
Tide
Wendy's

B

M&Ms
Rocket Mortgage by Quicken Loans
Budweiser
Sprint
Groupon
Australia Tourism
Jeep
Pringles
Verizon
Bud Light
Hyundai
Pepsi
eTrade
Water.org/Stella Artois
Wix

C

Universal
Turkish Airlines
ZzzQuil
Modelo
Febreze
Toyota
Michelob Ultra
RAM
Coke
Kraft
Turbotax
Lexus
KIA Stinger
Intuit
Monster
Persil

D

Skechers
Advocate Health Care
Blacture
Heroes Arena
WeatherTech

F

Squarespace
T-Mobile