Big-Lipped Alligator Moment: At one point Mike fights a Giant Spider in the basement, killing it by flooding the basement and electrocuting it. But when the bad teenagers steal the Goo moments later, there is no water in the basement, nor is there any sign of the spider's corpse, and the whole incident is never mentioned again.
Fridge Horror: The teens all end up cooking and eating the giant ducks - which have very recently eaten the Goo. Now, like snake venom, one can assume it cooked out in the process - except that can you be sure? Gigantism aside, the chemicals used to make the goo could become toxic under heat. Not to mention the effort it took to kill and prepare two giant ducks.