Oooh, the nervous look ones. You have to understand, there are a lot of experiments I do during production to try to get the "feel" right on things. Most of the unused stuff gets cleaned up, some is just left there. These were made for a very specific set of circumstances, and I THINK at least some of them are used in game, but I can't remember specifics at this point. I will say that once you hit slut mode, actually fighting becomes basically impossible, and you "win" by fucking all the boars to satisfaction in a fight. The one set you've circled in the first one is for that: it's a "victory" sprite, but you won by slutting it up, so it's a different sprite. I'd have to dig through the code to figure out if the others ended up being used or not though, and it's not worth the time/energy at the moment. I will say, if you haven't already: 1. hit slut mode. 2. Voluntarily remove clothes. 3. Fight and "win" several fights. You MIGHT see some of this in that configuration.
On the Mahir/Diezel stuff: Again, the Mahir image with the background is promotional image. The one used in the game itself has transparency. There's why there's a difference. On Diezel, again, I go through variations of things. But whatever ended up used in the game is what I settled on in the end as the preferred usage.
On enemy detection: This is not a highly-advanced stealth game. Mob detection and seeking of the player isn't even included in base MV, it has to be added via plugin. I have one toggle I can swap: direct line of sight, or proximity detection. That's it (related to this issue anyway). So I have them set to simple proximity in this case, because I didn't want the boars to not see Mezz if he went behind a corner or bit of clutter etc. Again though, first game, very basic configuration. GT is a little more refined in terms of design, although even then, possibilities are somewhat limited by existing tools. Not a bug though, just how the code works.
"They also started walking unpredictably fast in different directions after they stopped chasing, apparently due to the fact that they are far from the places where they originally were." Again, my understanding and implementation of the chase plugin was a little crude in this first game. It works well enough to get the job done. But there are a lot of rough edges in terms of design and so on that just aren't going to be addressed in CS, because it's not worth the time investment. It runs, it doesn't crash, it's mostly reasonable and playable, which is good enough. I learn each game, and improve each game. But you have to keep diminishing returns in mind when working on projects like this. Sometimes it's better to just move on and make the next one better.
"I just can't understand what this censorship means, what exactly is censored here? I know it was done on purpose, I'm just curious."
Read the text in your own screenshots. Mezz's reality is being twisted by the clips, so he doesn't actually understand what the boars are saying. Anything that would "spoil the fun" too early just loses its ability to be processed by his brain. What SPECIFICALLY it is doesn't matter. It was just a little too much information, so the clips censored it.