I think we will never find a universal fix for the screen mode and resolution problems of Win10 unless Microsoft introduces some new compatibility option, allowing the system to obey screen control API functions exactly as it was done in some earlier OS
version, at least allowing Win7 compatibility in that regard.
For some games there are alternative solutions though, based either on the configuration options of the games themselves, or based on configuration options of compatibility/emulation engines used to to run games that are no longer compatible with modern
OS without those engines.
One such emulation engine called DOSBOX has become commonly used for many old DOS games (or Win3.x games), and is regularly used for most such games by the 'GOG' brand. (short for "Good Old Games"). And for this engine I have found one fix that helps with
all DOSBOX games/setups I've tried so far under Win10, including some bought from GOG and some I prepared for DOSBOX myself.
For such games you need to edit the "dosbox.conf" file, sometimes slightly renamed for GOG games, and in that editing change some of the config variables in the [sdl] section from their default values. The main variables involved are "fullscreen" changed
from "false" to "true", "fullresolution" changed from "original" to "1920x1080" (or what other physical rez Win10 uses on your PC), "output" changed from "surface" to "DDraw" (some other modes also work, but DDraw was best for me so far).
Those three settings solved the problem for most of my DOSBOX-based games, causing them to display in full screen height, with some left+right black bars (to maintain proper aspect ratio).
One DOSBOX setup I treated a little differently so as to make the most of its own rendering abilities, and that was the "Windows 3.11" setup, which I use mainly to run the oldest Windows versions of Civilization and Colonization. To make the most of this
I first used the config commands of that old Windows version to switch its rendering to its highest available resolution of 1280x1024 pixels with 8bit colors (256 colors). Then before the next launch of this Win3.11 setup I also edited its dosbox.conf setup
almost as described above, except for setting "fullresolution" to "1280x1024", so as to avoid the need for non-integral pixel scaling (with the full 1920x1080 setting it got noticeably slower). When launching either of the two games I mentioned in this Win3.11
setup their ingame map windows can then be maximized to use the full 1280x 1024 resolution for the game rendering, with just a few pixels each wasted at top and bottom of the screen. The horizontal waste is of course much larger, but that is the cost of maintaining
a proper aspect ratio. Personally I wouldn't want it stretched to fill that width...
I hope the little guide above can help some other DOSBOX users.
As for non-DOSBOX games, I have had some success in making "Sid Meier's Alpha Centauri" run in full resolution. But I was not able to do it with the GOG 'Planetary Pack' release. I could only do it when installing it in the traditional way, starting with
CD ISO, then adding update and compatibility patches one by one. When done this way I could simply use my replacement '.ini' file to make it work as I wanted.
The main trick to this is to include "DirectDraw=0" as the first option entry in that file.
The same rule also applies to the '.ini' file of "Civilization III", where I also have "KeepRes=1" on the line immediately following "DirectDraw=0".
And of course, I run both those games with a Win10 compatibility setting for WinXP compatibility.
For both of these games some of the intro screens look a bit weird, with lots of black borders, and I think the same will apply to some of the ingame movie events. But this is to be expected of games originally designed for much lower rez than they now must
run in, and the main game map and all normal menus will work as expected using the full Rez.
Best regards: Ronald Andersson