I was just going to read this and move on but some of this is just rubbing me the wrong way. So I'm sorry if this is coming off as either being blunt, harsh or overly defensive.
I'll change it.
There is a window without a window frame.
Which one? Be specific, this is extremely vague and unhelpful.
The plaster material is really weak and it is not fit for supporting stone bricks and making large structures.
Plastering is used to cover existing brick work as a form of protective or decorative coating, which is kind of the whole point of plaster? I mean, you could argue that it looks like the entire room is made out of plaster but that wouldn't be how plaster works in the first place. Plus then you could ask why the top isn't covered as well. But that would be an easily self-answering double-edged sword if you really wanted to go there.
I recommend using mann manor or a castle style for the building.
I'm trying to go for a mix between Manor & Castle in the first place. I mean, why try to stick to the same themes if you can attempt to create your own? I know the response to this would be something like "well you're not doing a very good job at it". But these things are subjective to most people. I mean, I'm not trying to be dismissive of this but it's just that I'm trying to do something different from the norm and not everyone can or will see it as such. It's sort of the same way that you can't make everyone happy.
There is not much explanation as to why would anyone want to capture the last point since (from what I can tell), it is practically a kitchen in the middle of a big, big room. The kitchen makes no sense to be there unless there is a huge, long medieval dining table very near. (even so, it makes no sense to have kitchen in a broad space.)
Tbh, it's hard to see the transparent pizza intel bag I have in that screenshot. But also, lore wise Merasmus is a wizard who's capable of slaughtering all of the mercs yet is helpless and terrified of whatever mafia or gang he happens to borrow money from. Meanwhile we had the two mann brothers who believed gravel was the center point of the world and we didn't even know that until it was explained in the comics. So asking for this kind of thing when the game has repetitively thrown it out the window is asking for a lot.
If the halloween portal wasn't there, the building would essentially have a big hole on its ceiling. Makes no sense. You can put a simple narration like: "A portal was opened by a some evil magician and broke the roof."
Kind of hurts that you didn't notice the big ray gun pointing up at the portal with the glowing tip. I guess I'll need to detail that section level with the ray gun to make it more apparent that it's more of a lair type setup.
I would like to see more erratic changes to the geometry of the room since anything above the second floor can basically be anything else. You can make, idk, a town with a huge plaza in the middle, a garden of a mansion, or anything you imagine as long as the gameplay remains similar. (actually even the gameplay can change drastically like how they did with helltower)
Helltower added Spells, The Witching Hour, One Extra Death Hazard and an Underworld/Hell. Outside of those 4 things Helltower remained mostly the same outside of visual changes. But I guess instead of keeping it a surprise there is going to be a custom monster in the map along with an Underworld, Pumpkin Bombs and Spells I haven't added in yet. Plus there's the whole spin on delivering pizza to the Underworld.
Not every map has to go wild with redesigning, especially since I specifically wanted to do a reskin that preserved most of the existing brushwork. The original idea being that Merasmus needs help to get out of trouble and the location happens to be in a spookie trainyard with two evilish lair bases.