Age of Darkness is what you get when you cross They Are Billions with Warcraft 3. The game is competent in most aspects, but there are definitely some things I wish were different.
While the game puts a lot of emphasis on careful and defensive play, there are two different game modes, and even though there's zero divergence in mechanics or even number values, I found them to be vastly different.
The Singleplayer Campaign is heavily influenced by Warcraft 3. From the way that the sotry is told through ingame cutscenes, character abilities and even the mission structures themselves. Some missions don't even allow you to build structures, but instead gives you control over a handful of units accompanied by a hero who explore the landscape in order to reach a target destination, kill a certain unit or fulfill other mission parameters. The are still a lot of missions that require you to build and maintain your own base, and quite often you also fight rival factions rather than try to survive spawning hordes. In short, it becomes a regular RTS and you even have your own Hero character that you level up and acquire new abilities for. There are 3 different factions you play as, and they all have different hero characters with different abilities. Apart from that there's not a huge difference between them. They all share the same tech, buildings and units, but they are also able to produce a few unique units that the other factions don't have access to. These units, however, are too few and still too similar to really set the factions apart.
The backstory/lore of the world is quite compelling, but unfortunately the narrative and written dialogue are terrible. Characters are cartoonishly one-dimensional and their reactions to events seem to be driven by a need to push the plot in a certain direction rather than their own motivation. There are some plot twists, but they are so obvious you figure them out long before the game even starts hinting at them. Voice acting is surprisingly great, but it wasn't enough to stop me from disliking literally everyone.
The Survival Mode on the other hand does away with the story altogether. Here is where you slowly expand your base while simultaneously defending against ever growing waves of spawning enemies. This mode is extremely similar to They Are Billions with a few exceptions. There's a timer (measured in days) between each new wave, and you have to explore and set up your defenses ahead of time to make sure you'll be able to survive. You won't know where they're coming from until just a few minutes before the wave spawns, and they don't always seek out the closest route to your town hall, so predicting where you need to focus your defenses can be tricky. Once a wave spawns, any area not revealed by your buildings' line of sight will be covered by impenetrable deah fog. You cannot see through the fog at all and new enemies spawn inside it, so unless your soldiers are securely in your base you''ll have a hard time bringing them back.
Once a wave has been cleared, you can once again set out to explore, expand your base, and claim natural resources to improve your economy so that you can further improve your defenses ahead of the next wave. And that's the core game loop. Explore -> Expand -> Defend -> Redo.
Both these game modes are very different, but still work quite well with most aspects and features. It seems the devs were split on doing two different things at the same time, but somehow managed to pull them both off quite well. The only downside to this is a lack of content. I am no big fan of the campaign due to the writing, and while I really enjoyed the Survival mode, there's really no reason to replay it unless you want to try it on a higher difficulty. There's nothing new to unlock (except the next difficulty). No new maps with different rules, mutators or themes. It's all the same, which is a big shame.
Another very frustrating aspect with the game I found to be the art style. The game is beautiful, but it's so detailed that it wears on your eyes. I always found myself strained to make out different units and level aspects and there's barely any moment when you feel like you can rest your eyes.
The game has problems, some of which cannot be fixed without a massive revamp. Still, I enjoyed my time with it and would recommend it to fans of the genre.