I'm giving this episode a six not because it's boring the pacing makes a snail seem like a cheetah on steroids but there is one major flaw with the Dick Roman's plot to conquer the earth. Oh god not another one of these.
Dick Roman aquirred Sucracorp sometime during season 7, his intention was to come up with some sort of additive that would make us the human race more easier to catch and eat. After several failed attempts to develop the serum ("the turducken syndrome") where people literally morphed into flesh eating zombies, he finally perfected it and added it into High Fructose Corn Syrup which as you all know is in everything processed, from soda, to twinkees crackers, cookies to even canned fruits n vegetables. The corn syrup is then transported to companies such as Coca-Cola, and Nabisco to be added in with their products. The tainted products are then shipped to all grocery markets and mini marts, turning these poor souls who ingest the food into mindless drooling zombies.
Considering how long it would take to develop the formula then add it to the corn syrup you ould have to figure out exactly how long it would take to properly mix, and how much is needed to the corn syrup supply in order to become effective. Then figure how long it would take to ship and process and then add more time to package and ship to all mini marts. Supernatural explains lil to none of those things and expects the viewer to believe in that short time all of this could be done in a relativly short time frame.
Also even if I am wrong nd in the time it takes to properly manufacture and distribute tainted supplies and add to america's most loved products is correctly written, the entire country would not be affected at one time nor would all of America's food sorces be affected. First off there are several companies that deal in Corn Syrup, so only a small portion of product would have Dick Roman's syrup. A good chunk yes, let's say that Sucracorp sells it's syrup to Coke but Nabisco has their syrup brought from another company. Then figure distribution it's assumed by the writer that distribution would affect everyone at once, not so. Distribution would only affect those in some areas at first and then spread.
Also the writers ignore that the government would not be involved somehow. I would think at some time someone other than Sam and Dean would figure out there is a zombie epidemic the FDA and the DOH would investigate and come to the conclusion somethings happening, he may have some government offices under his control but really something this large is not going to go unnoticed. Also think of our allies somewhere in Britain, Russia, China anywhere that imports our products there's no way Dick Roman's hand is that stretched.
I know Supernatural has had some farfetched stories in the past but those mainly involved opening the pits of hell, another demension and a full on demon apocalypse. This season is grounded too much in reality and with a show like this it simply doesnt work.