I've made further attempts at installation and, after an epic multi-hour install, attempts at actually starting up the game. I thought I'd outline some details and see if you can provide me with any further help.
I have a fairly new, Core i5 with 8 gigs of RAM, and I'm running Win 7 64-bit. I had no issues installing or playing the original Hegemony: Philip on Steam. My internal hard drive is partitioned into a system partition and an 'Apps' partition (for most non-utility or system programs, such as itunes, Steam etc...). I also have a couple of external hard drives. Other programs run fine (Deus Ex Human Revolution, Witcher 2, Civ V, VLC media player, Firefox, Office, the list goes on). As far as hard drive space, the System partition has the least amount of free space at around 92 gigs.
The first time I tried to install, I downloaded the installer to my main external drive, and tried to install Hegemony to the Apps partition. As I said, it took a long time. I finally left it installing for many hours and it did complete. I then tried to run the program, and while 'Launcher.exe' showed up under the processes in Task Manager, nothing else seemed to happen. I walked away from my computer, to return an hour or so later, and lo and behold, there was the game launcher, though clicking play achieved nothing.
I then unistalled Hegemony and deleted the installer, and the downloaded the installer to my desktop and tried to re-install it to the default installer location (C:\Program Files\...). Same issue, an extremely long time to 'Decompress Sounds'. Again, many hours later, the install completed, and once again, nothing seems to happen upon starting the launcher (I haven't let the launcher run long enough again to see if it will appear hours later).
So... there you go. Do you need any more info? Have any other ideas?