Ashes of Erebus is, above and beyond everything else, an immersive, TBS, fantasy experience. (I must give due credit to the base Fall from Heaven II mod, though.) It’s better, in my opinion, than any fantasy 4X since, including the likes of Age of Wonders III or even Endless Legend (although the latter comes very close).
Incredible depth has been achieved with the diverse civilisations, beautiful and bustling fantasy world, and responsive game mechanisms like the Armageddon Counter. AoE’s contribution of improved flavour starts, expansion of unique city graphics, improved AI, and expanded alignments (among other additions) go a long way to rounding out what FfH2 started.
But. It’s still lacking polish in some areas. The artwork is spot-on, but the lore – one of FfH2’s strengths – is becoming patchy. The Civilopedia, while generally informative, has holes. There are text-holders in some in-game pop-ups. The game crashes more frequently than I’d like, and I sometimes have to load a save a few times before it works. Honestly, a lot of this is more noticeable than it might be in a comparable mod because a lot of the other additions are so well done.
When all is said and done, though, I really do feel like I’m at the helm of an immortal race of Romans ready to reconquer Erebus. And that’s what Ashes of Erebus is all about.
Civ IV was ahead of its time a bit with mod support, so installation of mods is actually pretty easy compared to its contemporaries. There are detailed installation instructions available in the Ashes of Erebus forum on CivFanatics, but for the general case of installation of a stable release, see the below.
Install Civ IV and it’s expansion, up to and including Beyond the Sword with the 3.19 patch. Most digital downloads will result in you getting the most up-to-date version (look for Civ IV Complete Edition).
If using the Steam version, in your Steam library, right-click on Civ IV, select the “Properties” option, navigate to the “BETAS” tab and select “Original release” from the drop-down.
Download the latest release version. At the time of writing, this is version 14.11 released on the 14th November 2014. The link to the latest version is available on the AoE forum. (I recommend using the SVN version because the latest release is quite out-of-date now.)
Unzip the downloaded file. It’s in .7z format so you’ll need to use an archiver that can work with this format, such as the open source and free 7-Zip.
Copy the Ashes of Erebus folder into your Beyond the Sword mod folder. If you’ve installed from Steam, this will be in something like C:\Program Files (x86)\Steam\steamapps\common\Sid Meier’s Civilization IV\Beyond the Sword\Mods. If you’ve installed from a CD this will be in C:\Program Files (x86)\Firaxis Games\Sid Meier’s Civilization IV\Beyond the Sword\Mods. (I’m not 100% on these locations – you may need to hunt around for a bit, and some of the directory names might be different if using the Complete Edition. If anyone knows definitively, please let me know in the comments.)