Before I go on, I have just got to say how much I love this game. It really reminded of games like Fallout 1 and 2 or Wasteland 2. But I def noticed some things that I think could have made the game even more immersive, although I feel pretty much all of my complaints are 100% petty considering what a great job the developer(s) did in crafting this game. Here are some of my ideas, so feel free to pitch in any of your ideas as well.
1. It would be kind of cool if the different types of headgear you wore would change/match the appearance of your avatar. I mean, if you purchase a helmet or some sort of headband, it just sometimes feels weird to be looking at your character's picture looking exactly the same.
2. I think another cool feature would be if everything you gather would be visible on your actual character. I mean I understand how ridiculous it would be to show off organs, and minor components on the character, but at least have the character carry a bookbag or something where they can store some of the smaller items. Hell, maybe if your character has high enough psi, he can just have a small purple ball of energy hovering just above him and whenever your character retrieves an item, the energy ball opens like a mini-portal for you to get whatever you need or toss whatever items you don't. Maybe in that case, your physical level of strength wouldn't matter but rather your level of psi, and depending on your level the more things that energy ball can carry.
3. Companion characters. Underrail is a big and interesting world with a lot of lore and some really well written characters, but it's a little disheartening to be traveling through the entire game alone.
4. I also found it kind of ridiculous at times how if I came across a locked door that I couldn't lockpick or hack, that I couldn't just use my psi abilities to rip the door off its hinges or literally melt it to the ground....or freeze the door and shatter it with a hammer. I'm just saying, it would have been nice for your character to have more then two options "open door" or "oh, you can't open a door despite having insane superpowers that can wipe out an entire room of armed thugs"
5. Multiple endings. I admit, I'm not really sure how many their are, but it would be cool if their were several. If there are then please disregard this.
6. Would be kind of cool if your character could hit a light jog rather then literally walk everywhere. Also, I think if your character could crouch or lie down would be pretty cool because then maybe that can affect your visibility and accuracy with long range weapons.
Well alright then, I think this is all I've got thus far.