I had the chance to try the new Stronghold HD. Here are the changes.
The game will start on the default monitor’s resolution. For me it is 1680 x 1050. It is a 22” monitor. It looks great on this resolution, the units and buildings are not small at all. Using this resolution, I barely need to scroll the map. I guess on even higher resolutions like 1900+, the player will see all the map without having to scroll.
There is an option that will zoom-out and show all the map, I’m not sure if this was available in the initial game. To use it, right click on any terrain and move the scroll to the right side.
I have tried the military campaign and seems that it is the same, there are no new units or buildings.
The graphic is also the same, nothing is improved.
So it looks like it is the old Stronghold that is now playable on high resolutions and it has no compatibility issues. It works fine on Windows 7, 64 bit. I have the gog.com version.