I think they should've gone in a different direction with story, akin to what Mike Amato suggested as quoted by B-Boy: I really like the idea of Duffman having to deal with the fact of having become a corporate puppet and having to get help to drag the man beneath the outfit out of there & patch together his life, but I assume that'd have been too complex for this episode...
So after the last episode ('Treehouse of horror XXXIII', which was an refreshing success) the show hits back with a story centered around Duffman (wanting to reconnect with his estranged daughter) and Homer & Lisa as his companions. Barry Duffman is best served as an gag character but to having him be the center of attention for an episode isn't a bad idea but opens up for good possibilities to explore the man behind the Duff Beer mascot persona & the possibility of finding out about if he has an family was interesting, but what we got felt a little underwhelming & lacked in depth. It had some really good & interesting moments throughout, but it felt pretty surface level with a missed opportunity at showing more of him as a real person (I think that to really make an episode about Duffman work, you'll need to look behind the spandex suit & see him as a person. There were such moments, but it often bounced back to him assuming the persona again) plus the Homer & Lisa conflict was nothing really super new so in the end, it didn't really do a whole lot for me. Still fine though.
The opening with Duffman being in danger of being replaced as the Duff Beer mascot during the new mascot election campaign (as his popularity is going down the drain) was nice & felt a bit topical (as the character can be interpreted as misogynisitc, I guess), but other than the very opening with the sequence of "Duffman through the years" (as I'd call that series of commercials showing the character in the 1950's, 1970's & 1990's) nothing was especially funny (well, that moment of him tricked by a a misleading sign and angering a bunch of women was a fine joke, but then they did two more directly afterwards and it got too much. Felt like a very Jean kinda joke as opposed to one by Selman). Homer leading a private campaign for Duffman with his friends was all right but a little pointless (as we never saw them afterwards) and Marge & Lisa sitting by the TV, scowling & being angry at Duffman was a little exaggerated (I get why they would be irked by his campaign, but they never cared about him to this extent before, but it was still a nice way to introduce the main conflict).
I did like how both Homer & Lisa got involved with Duffman when the latter pulled out an old photo from some Duff event (on which he sits with a younger Lisa on his lap) to lie himself out of a corner by saying she is his daughter. The two confronting him about the lie led to a nice little scene where his real self (Barry) gradually starts to break out from behind the persona: Duffman being impressed by Homer's bond with Lisa & then saddened because it reminds him of his estranged daughter Amber who wants nothing to do with him was interesting (I enjoyed that they started doing something with the character, showing a bit of a regular, flawed guy) & the following scene with Homer's girl-dad group helping Duffman to prepare him for contacting his daughter was OK but felt a little extraneous (felt superfluous with all the characters for a relatively short scene & the dads banging on the glass as Duffman's calling Amber came off as a pretty lame joke, but the Chinese restaurant gag (PF. Thongs) was actually pretty funny; the stone lion statues having thongs was an amusing visual joke).
So the following road trip (which Homer makes with Lisa & Duffman) so the latter can reconcile with Amber, was nice, but like most of the prior parts of the episode, it only had smaller moments & sequences that really stood out. Homer taking Lisa with him under false pretenses (that she could go to an Agatha Christie Museum) felt like an obvious setup for a conflict (as something inevitably would go wrong), Lisa suddenly stating she likes K-Pop and then it goin to them doing a random sing-along in the car was pretty charming (A highlight of the episode; loved that spontaneous energ), the restaurant scene was a nice expositional bit & them stopping at a convention so that Duffman could futilely try get supporters was alright at best (but the joke with Homer having been looking at a fake clock of a mascot was a little funny, but wasn't a big fan of regression of Homer to a dumb careless bad fathe, especially after episodes as of late having shown him in a more positive light where he does a decent job as a dad and even give good advice. Still, a plus was it was an honest mistake).
Then we have the inevitable conflict with Lisa being (understandably) upset and angry at her father for having gotten the time wrong and leading to Lisa missing out on visiting the Agatha Christie museum and refusing to talk to him: I understand Lisa's disappintment and sympathize with her (and her outburst was well acted by Yeardley), but the thing is we've seen this conflict play out a lot before (Homer gruesomely disappoints Lisa in some fashion, Lisa is angry and Homer us regretful & they end up reconciling soon afterwards) and it felt like it took focus away from Duffman (who randomly goes on a date with the museum curator). Fortunately, their conflict got resolved quickly when Lisa, in the car with Homer, found the drawing Duffman's daughter had made for him when she was little; we've seen the following scene before, with two people (Homer & Lisa) talk about another couple of people (Duffman & Amber) but really are talking about themselves and their conflict, but I liked how they solved their issue by talking with each other; that was good writing).
While he remainder of the episode wasn't anything unique, it had its moments: there was an interesting twist bit, with Duffman going to his daughter's condo and being tempted by joining a pool party & when Amber answers the door, it's Homer & Lisa instead; I at first thought it was due to Duffman having gone to the wrong place, but then it turns out it actuallly was the right place after all with the party going on in the backsground. I do think the double twist/faktout was unintentional and it's just the staging of the scene (as it is silent in the background when Lisa and Homer talks with Amber & they undoubtedly would've noticed Duffman), but still kinda liked that fakeout (despite how, as said, it doesn't make any sense they'd didn't hear or see him). The rest was pretty standard, but not bad: Duffman having disappointed his daughter again and she runs off, but he saves her from being hit by a rolling beer keg with his giant magnet (the "Chick-Magnet") which he seem to pull out of hammerspace & he is pretty much all forgiven (it felt a bit quick and cheap, but it wasn't too bad).
Duffman torn between his job and his daughter is the expected dilemma & Him quitting his job as the Duff mascot was a little surprising (but he'll no doubt be back to his usual game the next time we see him) & he dedicates his time to be with his daughter... and then they do the subversive twist that he's helping her promote her marijuana dispensary. It felt like a Scully-ish ending, but not in a bad way and the absurdity of him having quit the beer business to be in the drug-selling business instead was inventive. Yet in the end, it was still a bit of a shaky story, with Duffman opening up as a real person and sometimes reverting back to his persona (I think the restaurant scene with Homer & Lisa was a good example. Every time he felt like a real person it immediately got more interesting, but they often had him turn back to the "Oh yeah!" schtick. I wish they'd just have him consistently opening up instead of having him bounce back and forth) & his daughter Amber was just there, pretty much (a waste of guest star Aubrey Plaza. She got nothing to do). It wasn't bad, but far from great.
I'll give it a 3/5 (rounded up from 2.5/5). Not the most original plot (with a lot of reused aspects & storybeats), it felt a little uneven and somewhat surface level (as I feel they could have done more by exploring Duffman than "only" an estranged daughter plot), some scenes felt a little pointless (and so did the election plot, which they almost forgot about), a lot of incessant jokes (few of which really worked) when this should've focused more on the drama of the story & the guest star characters were so-so (and Homer reverted back to being a incompetent dad I just couldn't really let go). It had its good moments that I enjoyed & it was still coherent and decently paced, but as a whole it didn't fully deliver on its premise & ended up feeling too much like, well, another standard fare episode (I think more originality, creativity and energy would have done a lot for it). But still, I think it was fine enough and wasn't too bad.