>>>2019 update<<<
Heya guys, I come with a tiny update! I know...this game is so 1999.

ANYWAY! Let me get to the important part: playing IMP II windowed (on WIN10 in this case)

You should get DxWnd; this is a "windows hooker [that] intercepts system calls to make full screen programs run in a window" and "it is typically very useful to run old windows games." You can find this open-sourced program and more information about it on sourceforge.net.
With that rabbit out of the hat:

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1. Install GOG Imperialism II version 1.03 and extract DxWnd v2.05.03 somewhere (these are the latest versions at the moment of writing and what I've tested)
2. Run DxWnd as admin
3. Click "Edit" at the top and "Add"
4. Link the "Path" to Imperialism II.exe and replicate the settings.jpg attachment
5. Run the game from DxWnd and have fun
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MULTIPLAYER

I played a LAN game from start to finish with no crashes whatsoever.
Make sure you allow the game through the firewall (on every PC). I did not save/load in this playthrough but from my past experience (it used to crash when connecting to the host), it WILL go through if you try many times.
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Words of advice

Be MINDFUL of what you change in DxWnd because I managed to break IMP II so badly that no ammount of reinstalling/cleaning the registries/ reinstalling direct3d/directX/whatever could stop it from crashing; idk what kind of transmutation magic that thing does ( though if you undo -in DxWnd- what was changed -in DxWnd- all will be peachy again ).
IMP II worked for me from the get go; the most common issues are the lack of Direct3D, DirectX | also make sure you set the game to run as admin, diable fullscreen optimization and run in XP2 compatibility mode.

Thank you very much for your post, the information is really appreciated. This is a real useful tool!

Thanks man, I've been looking for solutions to this.

More detailed instructions on how to run it in a window, with scaling:

1. Search for "DxWnd SourceForge" and go in there. Go to Files, Latest Build, and download the newest build.
2. Unzip it somewhere and run it.

SETUP
3. Edit->Add
4. Name: Imperialism 2
5. Path: C:\Program Files (x86)\Imperialism II - Age of Exploration\Imperialism II.exe
6. Window Initial Position & Size: 50, 50, 800, 600
7. Ok
8. File->Save

TWEAKS
9. Right click on Imperialism 2, Modify
10. Main->Generic->Hook enabled
11. Main->Generic->No banner
12. Main->Generic->Run in Window
13. Main->Generic->Hook all DLLs
14. Main->Generic->Remap Client Rect
15. Main->Generic->Use DLL Injection
16. Main->Generic->Hook child WindowProc
17. Video->Windows handling->Fix Window Frame Style
18. Video->Windows handling->Lock win coordinates
19. Input->Cursor Visibility->Automatic
20. Input->Correct mouse position
21. Input->Force cursor clipping
22. Input->Keep cursor within window
23. Input->Keep cursor fixed
24. Input ->Intercept GDI cursor clipping
25. Input->Fix WM_NCHITTEST
22. File-Save.

* You'll need to run dxwnd.exe as adminstrator.
* I have been able to find any settings that render at a higher resolution without frequently crashing.
* Therefore, the only way to play it at a "higher resolution" is to lower your desktop resolution to 1024x768 or the like and let the monitor upscaler do it.

Unfortunately, further experimentation has shown that you can't run it in a window with DxWnd upscaling to a higher resolution without crashing. Instructions updated.

Hi there,
Appreciate the effort in writing these instructions.
I have DXWnd 2.03.76, and it works good - but with a keyboard glitch. There are two scenarios where the keyboard is required:
- When saving the game, I cannot enter any characters - at first I thought it is only invisible to me, but the save game name gets set to "Unused" whatever I try to type.
- When trying to modify the number of units in trade offers. So, if Italy offers me 3 units of timber and I want only 1 there is no way to modify it.
Actually, I do not even see the letters/numbers in the field where the user input is expected. So my conclusion is that the keyboard is not even detected.

Have you seen/dealt with this before with DXWnd? Any tips?

Cheers