Although this was released a little over a month ago, I just found out about it today.
So, I thought I’d throw this out there for others on here that didn’t know about it either.
Steam user Adamu-kun?! writes (source):
…the HUD works correctly, all screen-filling 2D art is stretched, all HUD items are properly placed and unstretched, 3D viewport is indeed wide. FMVs seem to be handled in a reasonable manner, as well. FOV seems fine enough.
Note: I can confirm everything mentioned above. The only thing worth mentioning is that the camera is zoomed in a little more than the original 4:3 aspect ratio.
Note: Make sure to edit the h3.ini with your desired screen resolution.
Bonus: Another IOI classic, Freedom Fighters widescreen fix was released just yesterday as well! Score!