An American businessman takes to Twitter to make bigoted remarks from another era and makes more bigoted remarks in a debate while threatening to run for the presidency of the country. Things get so bad that one Seth Rogen tries to escape to Canada while the other is deported back to the Old World. Their problems are only solved when they hit upon the power of nepotism.
Beyond that half-witted satire of America, there's also the secular Judaism of the modern man clashing with the traditional, religious conviction of the ancestor. But, mostly, "An American Pickle" is just an amusing premise that's barely developed beyond, say, "Encino Man" (1992). The opening scenes are pretty funny, including scientists supposedly explaining how a man could be brined for a century in perfect preservation to awake in the modern day, but the supposed scientific explanation of which is muddled by Rogen's voiceover narration humorously only stating that the scientists proved it to everyone's satisfaction.
After Rogen meets himself in dual roles, a cinematic trick, by the way, that itself is over 100 years old (e.g. Georges Méliès forming a band with seven versions of himself in "The One-Man Band" (1900)), the picture quickly becomes less interesting as it follows a familiar formula--one even used in rom-coms--where the couple break up and eventually reconcile. The difference here is that Rogen is in love with himself--even more so than usual. Give him a great actress, say Charlize Theron, to play of off, as in "Long Shot" (2019), and the formulaic nature of the thing may be somewhat overcome, but even for someone like me who finds Rogen's comedic talents partly amusing, two of him is a bit much to entirely base a movie upon. The pickle quickly becomes stale.
