In plotge of all types, whether they are chuunige, kinetic novels, horror suspense, or mysteries, infodumps are ubiquitous throughout the VN world. Infodumping in and of itself isn't a horrible thing to do to the reader (as some people claim), but it is a tool that is often abused by writers who want to expound on their beloved world and its characters.
First, the definition of an infodump is a scene with little or no dialogue where background information is provided without directly proceeding with the story. Infodumps can vary in size from as small as forty lines of narration to up to a thousand, depending on the writer and the subject matter involved. There are even multiple types, which I will describe here.
The Lump of Infodump
The Lump of Infodump (as I put it) is the most common type of infodump in VNs. In the 'Lump, a great amount of information, sometimes with brief bits and pieces of dialogue or character stream of thought, is provided in a single scene, interrupting the story. The 'Lump is the type of infodump most likely to drive people crazy, due to its tendency to create walls of uninterrupted text. When abused, it tends to interrupt and/or destroy the flow of the story, and I've encountered a number of games where a more measured approach to presenting the setting or explanations of the particulars of an event or the 'why' of an action would have been less monotonous. In fact, that is the big flaw of this type of infodump. It is almost impossible to avoid monotony with this kind of infodump, because all it is doing is literally dropping information on you. That said, infodumps often have a reason for existing that becomes clear in coming scenes, so it is not necessarily always a bad thing.
The Scattered Infodump
'Scattered Infodumps' are a technique where the writer provides the information in smaller, more digestible asides throughout the story, as it becomes relevant. This technique tends to be received with less irritation and often goes almost unnoticed by the reader, because it doesn't go on long enough to disrupt the flow of the story. Unlike the 'Lump, it is less likely to be abused, though many writers who use it get into the habit of always using it, which can be problematic for those with an allergy to non-dialogue text, lol.
The Flashback Infodump
The Flashback Infodump is just that, an infodump provided in the form of a flashback instead of an aside. These often fill in the gaps in the motivations of characters or their upbringing, and their purpose is, 90% of the time, to reveal something that would have made things less interesting if it were revealed earlier. Flashbacks are often abused, though. They are common throughout VNs, with roughly 90% of plotge having at least one and 30% of all charage (in my experience) having one. They are a convenient method of revealing a character's past, so many games also use them for character development, particularly in heroine paths.
The Prologue Infodump
This is probably the least annoying of the 'obvious' infodumping and is a sub-category of the 'Lump. Some games, rather than dumping setting and character information on you mid-story, will instead infodump immediately after you start. This has the advantage of getting around the disruption of the game's flow that is inevitable with mid-game 'Lumps and providing background information without the writer having to remember to include it strategically throughout the story. This technique is, however, rarely used. Games that use it are rare mostly because if the first thing you see when starting a VN is a wall of text, most people will drop the game right then and there. Because of this, most games that use this are directed to a very specific fanbase or niche of the VN community that already has an established interest in the game in question.
A few thoughts
The reason I decided to make this post was because of a conversation I had with @fun2novel regarding infodumping in Bradyon Veda. In Bradyon Veda, infodumping is integral to the game's battle scenes (incidentally the discussion began with me giving examples of good battle scenes to him). Because the science-fantasy techniques being used by the characters manipulate matter and physical laws, there are infodumps built into the battle scenes, explaining what they are doing. Because of this, I noted that Bradyon Veda's battle scenes were an example of positive infodumping, because it was done in such a way that it enhanced rather than disrupted the telling of the story.
What am I trying to get at? Nothing, really. I just thought that people give infodumps a bad rap, when they have probably been infodumped without even noticing it.