There's nothing quite like going into an episode knowing nothing more than the title and a few words of synopsis.
The gags were pretty spot on here. I can't think of any specific ones that didn't make me smirk at least a little except the very end. Personal special mentions go to "I said, 'Eat your patties!'" for being unexpected, "Shut your talented mouth!" and, of course, the time card scene. I also liked how it was implied that Mr. Krabs was in the cash register for the entire first half of the episode, with him popping out again later to talk to Sandy. I was a bit bothered by the mix of his expression and his line delivery there, though. ("Right you are, Sandy." to "I've seen it before.") He looked pretty happy in spite of the situation, and suddenly snapped into being serious with the next line.
Jumping ahead a bit, the song... gosh, that song! I'm always glad to hear new ones, and this one was really something. It definitely gave me "This Grill is Not a Home" vibes, but here I don't believe it was intended to double as a joke itself despite having some very nice visual gags. The last note in particular really punctuated just how lost SpongeBob was. It's a very relatable situation to be stuck in, albeit under not quite the same circumstances.
The scene of SpongeBob as a phone with the disconnected message was gold, and might actually be my favorite moment of the episode. Sandy painting everyone unfortunately had another small audio/visual hiccup. Her mouth is closed while painting herself, but there are still voice effects. Fun note about the other character's impressions of SpongeBob, for those who didn't notice: They all still have something to do with themselves. Maybe that's why they didn't work. :b The little formula moment that came out of it was great, and didn't take over the scene. Blink and you'll miss it, but after SpongeBob snapped back to himself you can see Squidward cheering sarcastically and Plankton... looking genuinely happy? (Aww.)
Ending gag was an ending gag. Pretty standard stuff.
Overall, VERY happy with this episode! I'm particularly happy that this and "House Worming" took advantage of traits specific to SpongeBob in regards to his flexibility and porous nature. There are few characters that could do both of these stories the same way, and in the past there have been moments where these traits and others were seemingly forgotten, and not just for the sake of a different joke. It's just really nice to see that shine again, and I really hope to see more of that kind of treatment with him and the other characters this season.