Iberian Peninsula

Like this?

I love it.

The mountains have a very 'Lord of the Rings'/fantasy vibe. Which I like personally. I do think it would be better to put a pass/bridge in the mountains between Euskadi and and Burgos, or widen the gap some. Or straighten the border. Anything to make it a little more apparent that there's a break in the mountains there.

Still not absolutely convinced on the color scheme. But I'm terrible with colors and other than saying, "wah, I don't like it!" I have no actual constructive criticism.

Well let's see what others have to say about these topics.

I think that adding a mountain bridge would be overcomplicating things, (first close the gap with mountains, then create a gap) and with these mountains, it would be weird because theoretically mountains should overlap the pass so not easy to see them or otherwise a pass above the mountains would definitely look weird.

And about the colour scheme, I went with a red-green-yellow-blue one because there are too many regions forming a big lump, finding different and fitting colours is complicated when you have to find 13 of them+background+dead zones. Plus the "dull" colours add feeling to the map. The map has two layers of brown/yellowish tones to achieve an old look.

Just with a paint brush, tried to make the passes a bit more obvious. Just an idea.

Will do that on the north one. The south one... it may seem that Guadalajara and Zaragoza are connected

Agreed. Good eye.

Looks perfect for me. good job

Maybe take out a few mountains between Ourense and Zamora if they are borders. Looking dang near done to me.

For me it's very beautiful. But if I have to criticize something, I'm not a fan of the ocean textures, it's so grainy, it seems like a photo at ISO 3200. Also I don't know if the mountains should stay so stylized: there are drawing mountains much less stylized than that; and then non-colour mountains in a colour map don't seem the ideal thing. The edges of the map still they look a bit like a painting frame.

It looks like most people want to keep the mountains, but the majority want them filled in some way.
The shadow you added as a fill is a bit inconsistent, sometimes the sun is in the east, sometimes in the west & sometimes the north.
As I initially said, keeping the mountains unfilled makes them high maintenance and there are still a lot of inconsistencies in the whole range between Segovia & Madrid and Avila & Toledo. A number of overlaps which allow you to see mountains behind mountains and some that make the foreground mountain look thicker (bolder), as well as other small inconsistencies on the other mountain ranges, too many to mention.

The early cartographers would have hand drawn the mountains from the foreground to the background so as not to have overlaps and would have chosen a fixed light source angle for shadow effects.

In my mountain visual aids, I chose 2 different sun angles, but the same angle for the whole map in each case.

Everyone seems to like the concept of the mountains, so it's just a matter of time until I remove every inconsistency.

As you can imagine, I didn't really care about shadows, but I will try and figure out some way.

For the background it's just an old technique I found that seems to fit quite well the map. And I guess I could add some grain to the mountains to de-stylize them. I can do sth too to the frame.

Unfortunately Psymon, if you are going to have any shadows at all, you have to care about them, because they have to be consistent, otherwise there will always be something anti aesthetic about the map that viewers will feel unbalanced with and won't know why.