Hi there!
Thank you for your support and your feedback, it really means a lot! I wanted to address a few of your points, as I believe there is value in providing this type of insight to the larger community. In short, there are a mix of creative and technical reasons behind why I would not implement this type of feature, but let's dig into them a little bit.
<Minor spoilers below for anyone who hasn't played Chapter 2>
First, Den is a static character in terms of his visuals because he has a defined lineage and place in the story, although choice is given to the player over his actions. For what it's worth, while I would agree that his human form appears caucasian, his skin in DAZ is described by the artist as "Latin." Regardless, you could argue, why couldn't Cindy give him the choice of the illusion? Well, she could have. I simply chose not to incorporate this for reasons I'll go into below.
When taking on a project like this, it is critical to limit the scope as much as possible. Most first-time game projects fail because they try to do too much with too little. I made an early decision to keep player choices limited to two areas - relationship building and personality. There are some "other" choices, but these are the fundamentals. I avoided choices that would necessitate alternate visuals within the same scene, such as character appearance (with the exception of pregnancy which is coming later). There are of course choices which cause branches to different scenes or scene variations which requires additional imagery, however, these are strategically placed and relatively easy to manage by comparison. The existing character variation that I'm assuming you're referring to (Demon form vs. Human form) does not introduce extra images, only model/material presets. You are correct that alternate presets are not difficult to create. However, incorporating them as variations into every scene of a pre-rendered game is an entirely different story that I'll go more into below.
Let's assume I attempted this. What would that require? As I said, the game uses static pre-rendered visuals (with the exception of the slightly more dynamic sprite sequences, which Den does not appear in anyway). Through chapter 3, there are around 2,700 images in the game, nearly 700 of which include the human form of Den. That means if we had four character presets for Den, we would need to add 2,100 additional images to the game (just through chapter 3). We'd be nearly doubling the number of images in the game, as well as the file size of the game, for this one feature. We would also have to introduce logic in the code every time Den appears, instead of Ren'py's simple one-line scene statement.
We can extend the thought experiment further if we consider that implementing this feature might invite the question - why not allow variations in the witches' appearances as well? Maybe alternative grooming habits? Maybe a spell that helped Cindy with her bust size? These all create permutations for scenes with multiple characters in them. If there are four Dens, and even just two Cindy’s, then the same scene that only required one render now requires eight. You can see how quickly this gets out of hand. Games that are entirely sprite-based or use a real-time 3D engine are much more conducive to this. Pre-rendered games, sadly, are not.
Anyway, I hope you continue to enjoy the game. Remember that your purchase entitles you to all future chapters. Chapter 3 will drop here in a few days, so be on the lookout!