Most of the time 'Sausage Party' is exactly what you would expect. There's over-the-top vulgarity, endless food puns, ridiculous character names, potentially offensive stereotypes & definitively offensive sexuality. In a lot of ways it appears that writers Seth Rogen, Evan Goldberg & Jonah Hill wanted to be so sure that no one mistook this for a kid's movie that they went as hard as they could in the other direction. Some of it is chuckle-worthy, but the real meat (pun intended) of the film rests almost entirely in the third act. There are seeds planted that might make repeat viewings more rewarding, but any initial originality, surprise or cleverness is very disappointing the first time you see it.
'Sausage Party' takes place in a grocery store over the 4th of July holiday. We follow the anthropomorphic food items as they look forward to getting selected and going to 'the get at beyond' with one of the humans, who are understandably viewed as Gods to every product in the story. But soon our hero Frank (a hot dog) soon discovers the truth of what humans do to food. A honey mustard container with PTSD is returned and eventually tells the truth to a whole cart of items excited to be chosen. That scene is the lone early bright spot in the film as it starts to explore the mortality of food and has a hint of debate about torture v. Suicide and ends with a well done war movie riff exploring the battlefield that is a spilled cart. It's an interesting place to start as exploring the psychology of this short life span and how the food idolizes the only fate they have can be mined for an interesting story.
After the premis is set-up, the film begins to coast. It follows a pretty standard conspiracy plot as a group of food (led by Frank) explore the different sections of the store looking for their home aisle and the truth about the greats beyond. It's essentially a series of sketches with a revolving cast of characters until the finale starts to bring it together. Sometimes that can work incredibly well for a film, but after (and during) the set-up, the writers coast on mostly easy, obvious jokes. Did you know a hot dog is shaped like a penis and a bun kind of functions like a vagina? Don't worry, this film will remind you again & again. Maybe an actual douche could be the villain because he's such a 'douche.' Funny, right? What if all the ethnic foods have very strong accents and exist solely as stereotypes? Wouldn't Grits be a black man? And. Angels are Jewish so let's make it a worried mix of Woody Allen neuroses. Maybe the food can smoke pot for some reason, because this is a Seth Rogen movie after all. It's an r-rated, very offensive animated film (South Park did it better), filled with food puns (bob's burgers did it better).
I was exhausted from rolling my eyes by the end of the third act, and most of my theater (aside from a group of teenage boys) found it about as entertaining as I did. There is no explanation for any of it except that these are obvious jokes, so the 'character building' is already there. Think of it like Toy Story if Woody & Buzz did absolutely nothing but act like a cowboy and astronaut, never growing. It's the whole first act spread over 90 minutes.
Ok - now I think you have gotten a full dose of my frustrations so I'll move on to the positive. The religious allegory that starts with the opening song and is then mostly thrown to the side (other than some expositional scenes and a particularly pious bun) in favor of crude humor. However it comes back strongly in the finale, focusing on the debate of whether a fictional idea of the afterlife that makes food happy while its living is better than the truth or not. It's a pretty standard critique on religion but nonetheless well-done and interesting in this context. The different angles brought to it from various characters also finally gets a little more in-depth with them (there is an Israel-Palestine debate between a bagel & lavash that is pretty entertaining). It's a different angle than how Rogen & Goldberg explored the idea of religion in 'This is the End' and they seem to be unsure themselves which serves the films well. They use this method to explore ideas instead of preach to the audience (plus they have a sense of humor), which avoids most issues with religious films.
I won't get more in-depth on the good stuff (it's spoilery), but I can also assure you that the crude humor continues until the bitter end and goes out on something shocking, filled with some clever jokes missing from the rest of the film. There's also a meta joke at the end that hits the sweet spot for my sense of humor.
Most people going to see 'Sausage Party' will only be looking for stupid, crude jokes and it delivers on that, just not as interestingly as I hoped. If that' all you want for 90 minutes then go for it. However, there is also a little more intelligence ingrained in the later part of the film that mostly saved it for me. Overall I enjoyed it, I was just hoping for a little more originality in some of the humor.