There should be a video option in the game settings

You must do some exe hacking. Nobody has found hex codes yet.

If you have a D3D11 capable GPU you can use dgVoodoo2 to force rendering resolution to 1080p. UI size will still be maxed out at 1280x1024, but you won't have to deal with poor scaling by your GPU drivers.

http://dege.freeweb.hu/dgVoodoo2/dgVoodoo2.html

There should be a way, this is using the Dark Reign 2 engine, and the source for that is out and about on the web

As I explained already you can already run Army Men RTS in 1080 (or any other resolution you want) by forcing resolution with dgVoodoo2.

Running the game natively at 1080p will only give you a much tinier UI and no added visual fidelity. See attachments for screenshot comparison.

Though if you want to try a exe with the resolution limit removed:
https://drive.google.com/file/d/0BxNI1ZLwcC_EWXJrNEpNYWNEMDg/view?usp=sharing
You'll be limited to the first 23 resolutions your computer supports and be limited to 16-bit ones since those are enumerated first. dgVoodoo2 can force 32-bit color though. I didn't want to waste any time trying to figure out how to remove this limit, because I probably can't figure it out anyway and as I noted above I think it's pointless. Plus I'm hoping a future dgVooodo2 update will allow you to limit which resolutions a game sees.

I can confirm using dgVoodoo 2 works, but ZellSF forgot to mention some important steps:
- in the game options menu you need to select a 16:9 resolution like 1280x720, so the game is rendered in the proper aspect ratio and isn't stretched.

It is also great luck that the in-game HUD renders based on the resolution selected in the options menu, because otherwise it would be too small on higher resolutions and not usable.

For those who are not familiar with dgVoodoo, here are the download link and instructions. GOG uses these files for the games they sell here, so you can be sure it is safe.

http://dege.freeweb.hu/dgVoodoo2/dgVoodoo2.html

- Download where is says "dgVoodoo v2.54 (released: 25.04.2017)".
- Extract the archive with WinRar or 7-Zip.
- Open the MS folder and copy the three files to your game installation folder.
- Run the "dgVoodooCpl" configuration program and in the DirectX tab set your resolution. You can also enable anisotropic filtering and antialiasing there.
- Then click Apply and exit.