Hey dev! I'm from Twitter and I just thoughts that it'll be more appropriate to post my suggestions and wishes here.
1-Adding dialogues/internal monologue to Yasa based on her current state. For example, she might be a bit concerned like "my stomach hurts and I'm farting so much, this is so embarrassing " at the start but as she gets more desperate she'll start going "no no no! Please don't come out" etc.
2-Npcs will start murmuring once the smell affects them, at first not suspecting Yasa but eventually they'll start to notice and will beg her to stop or something like that.
3-This is my biggest wish by far; more npc interactions. Example: a passenger walks by and accidentally bumps into her, this causes the combo to increase and upgrade one of the dots; either randomly or the lowest colored one starting from blue. This is just the tip of the iceberg, I'll let you decide how many of these interactions you're willing to make but the gist of it is basically that.
4-A button to toggle a little circle that'll show a view of her butt and anus (I'm guessing she's not wearing any panties, please tell me she's going commando under that skirt!)
5-A choice of where to go next after exiting the train. Since you'll be adding a walking section I hope you'll also add different pathways we can choose that'll lead to different ending variations. I want to see her absolutely bomb an alley or a a trashcan!
6-A second chance type of mechanic where Yasa can stop pooping mid accident, which saves you from a game over. When on the walking section she'll leave trails of poop along the way too. This is of course only for the story mode and not for the endless mode. For the endless mode I'd like to suggest an interrupted pooping mechanic where Yasa can potentially be interrupted from pooping, it's pretty self-explanatory.
7-Dynamic expressions, lots lots of them. I'd like her to have more varied expressions based on her current desperation levels, expressions are really important to me personally but it's up to you of course!
This was a really great game! I had a lot of fun with it and even at its current state it's already a masterpiece, probably the best scat and fart fetish game out there, we're blessed to have you Katihima! And I agree with that guy, there's too little poop, we need more please!