Diddlebucker! consists of an all-night scavenger hunt around a city, set in 1987. It's intentionally reaching for a comparison with Infocom - the cover art and the era, for instance, as well as the fact that the scavenger hunt plot is somewhat reminiscent of Hollywood Hijinx. But the comparisons go deeper than that: The terse location descriptions, the level of scenery implementation, the extent of character interaction, the kind of puzzles and their degree of difficulty - they're all a good enough imitation of Infocom's style that, to me, Diddlebucker! plays more like an Infocom game than any non-Infocom game I can right now remember playing. (Thaumistry might be an exception, but of course that game was written by a former Infocom implementer.)
The 1987 nostalgia runs deep. For example, while you don't interact with them, many of the Diddlebucker! teams that you're competing against consist of real people who would have been well-known in 1987. I won't spoil the game by mentioning any of them specifically, but this child of the 1980s enjoyed that aspect of the game. (Why they are all contestants in this scavenger hunt remains unclear, but that's all part of the madcap fun. Also, younger players may not catch some of the references.)
Puzzle-wise, I found Diddlebucker! to be one of the more challenging games in IFComp 2018. It's not quite as difficult as Bullhockey! or Birmingham IV (although it's also not anywhere near as long as those two games are), but I found it harder than just about all the others. Well, the puzzles in Dynamite Powers vs. the Ray of Night! are, strictly speaking, probably more difficult, but Diddlebucker! is so much broader in most places that the search space for potential solutions is a great deal larger. (Diddlebucker! does feature somewhat distinct stages, though, which helps you mentally narrow down the options for potential puzzle solutions.)
One thing I will recommend to potential players: Pay attention to the scenery. That includes what appear to be ephemeral random events; some of these contain clues or can even be interacted with.
Overall, while I do think a few of the puzzles could use more cluing, I found Diddlebucker! to be a solid puzzlefest that I would recommend to puzzle-game fans.