These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
"Putt-Putt, save the zoo, Putt-Putt, save the zoo, Putt-Putt, save the zoo, Putt-Putt, save the zoo..." And it goes on and on and on.
Some of the in-game songs could also qualify, particularly "The Zoo Song," "The Time Continuum," "Go Putt-Putt," "Under the Big, Big Top," and "I've Got a Secret."
Ensemble Darkhorse: Rover and Mr. Firebird, to an extent. Both are well-liked characters, but they didn't receive much attention. Rover is a big side character in Putt-Putt Goes to the Moon, but his only appearances afterwards were working at an ice cream shop in Enters the Race and Pep's Birthday Surprise and attending the party at the end of the latter game. Mr. Firebird wasn't treated much better, as he only shows up in the beginning and end of Moon and Putt-Putt Travels Through Time, in the One-Stop Fun Shopstorytime coloring book storyA Visit to Mr. Firebird, and in the Tie-In NovelPutt-Putt: Lost In Time (he's also mentioned by Putt-Putt in Pep's Birthday Surprise, and his factory/lab is the setting of Balloon-o-Rama's Levels 21-30).
Memetic Mutation: Tippity-top! (From the UK dub of Putt-Putt Enters the Race)
Older Than They Think: Few people are aware that Putt-Putt Joins the Parade and Goes to the Moon were originally on the MS-DOS and not Windows.
Scrappy Mechanic: The vegetable picking in Putt-Putt Enters the Race. It's incredibly slow, tedious, annoying, and the fact that nothing can be skipped does not help anything.
That One Level: Balloon-o-Rama is debatable on this subject, but Levels 61-70 and 101-110 come to mind, the former mostly because of Level 69 mentioned below, and the latter because the levels in that scenery take forever to finish.
Unfortunate Implications: Level 69 of Balloon-o-Rama has pink balloons arranged in the shape of a heart, which soon fills up with white balloons. Ironically, it's also a That One Level for many due to the fact all balloons regenerate after popping them. Three times.