When it comes to the visual aspect of a weight gain game, one question can easily come to mind: how do you visualize the gain? Some games forego the visualization entirely and stick to letting your imagination do the work. Often these are either text-based games or pixel sprite games with only one set of character sprites. Where the weight gain is not explicitly shown, but implied.
Then you have one of the other prominent methods using things RPG Maker, where the overworld pixel sprites are edited to be larger. Sometimes this is coincided with a larger sprite to the side, showing the character in their full glory. To one side you have the actual gameplay, and on another is the player character, who gets larger as weight is gained. …Though this is at the cost of screen space.
So how do you like to see characters gain weight in games?
Well since I have a pretty vivid imagination, I usually like reading how the weight gain is visualized and how the character sort of handles the new changes (although I’ll admit I do accidentally go either slightly larger or smaller, a slight issue but a good one in a way). So playing text adventures (especially those that display the current weight in some way, like a scale or mirror or even as a visible variable) is really fun for me since writer take the time to show how the weight is being applied onto the character (like Sarah goes to College, where on the boat your character feels the effect of going up and down stairs when ever you use them).
I can’t speak for illustrations because I’m not an artist. I can, however, speak for writing.
In writing, I’ve long held the idea that it’s generally best to describe the effects of fat and weight gain rather than the raw appearance of the gain itself. Often, I find myself far more titillated when the erotica I’m reading details situations like stuckage or wardrobe malfunctions as a result of fat as opposed to pure descriptions of size, shape, and nominal weight. Hell, I’d go as far as to say that these basic descriptions are annoying— they feel sultry to my imagination.
Personally I like to see a progression visually, but imagination is great too.
Looking at this question objectively, both are great in their own ways.
VISUAL: this method allows the author/artist to bring to “life” their interpretation of the character(s) that they have created for the story and allows others to see what the he/she had in mind, but sometimes this backfires as some people will say “I imagined XYZ to be ABC”. Bottom line is it is the author’s/artist’s choice on what he/she wants in their characters.
IMPLIED/NO VISUALS: this method works great if the characters are described well and in a way that “paints” a mental picture, rendering illustrations not needed. Much like novels, descriptions can work to the advantage of playing with the reader’s imagination and letting them fill in the blanks on certain things, or one could be very descriptive and leave little for the reader to interpret. Then again, not everyone is great at imagining things and some might have a hard time visualizing the characters, places, etc.
Like I stated earlier, each has strengths and weaknesses and I believe it is up to the author/creator/artist to determine which is best for his/her medium (game, VN, IF, etc.).
If we’re talking text-based, then I live for the descriptions that come in that moment of realization: the pants that fit you last week “suddenly” don’t anymore; the scale you haven’t stepped on in days is showing an impossibly high number; the snacks you bought to last the week didn’t survive the afternoon. Usually this is followed-up on by the character taking stock of themselves, preferably in a way that uses comparative statements. This is how gaining often presents itself in my own life which makes these kinds of scenes intensely engaging for me.
Also, building off of what diorite said, the effects of gaining make up 99% of the pleasure for me, so descriptions targeted at fat interactions rather than measurements are way hotter, imo. There’s a tendency in some erotic wg media to use numbers as the core of flavor text that I think really drags down the quality of writing (e.g., “Your belly sticks out 8.5 inches from your body”). Even if you can visualize in an instant how much that is, it’s so matter-of-fact and lacks any kind of passion. Instead, I want to see the author paint a picture of that belly’s size to me: “You belly sticks out quite a ways from your body. While you can still get your hands around it, your fingers sink into your new softness with such ease that it takes real effort to resist just kneading it like dough. You are eventually distracted by the discomfort of your pants that seem to be digging into your sides more than your remember. As you adjust them for what feels like the tenth time today, you notice how much your gut is beginning to sag over the waistband. It can’t be time for a new pair already… can it?”
Descriptions of weight gain’s effects on the body should always keep the character in mind. How would they react to these changes? In what ways would the extra weight most impact their lives? Use imagery and descriptive language to really make the text seem alive rather than just a bunch of numbers calculated and printed to a page.