Looks very good.

It's not zombie hate, it's the reliance on zombies as the go-to foe.

As for your zombie/human comparison. Zombies don't have a history, they don't have culture, they can't encompass as much as humans can. They're an empty vessel serving as a now typical and familiar threat.

For variability's sake, yes, I'd like it more if the enemies were something else. Let's take Heroes of Might and Magic for example. Is the game more interesting, due to the different types of castle/dominion one can use and therefore employ the services of different monsters? Certainly more than if the only possibilities were different types of zombie. Especially because of the prevalence of said zombie in recent (well, since Resident Evil) gaming releases.

All being said, zombies can be very effective enemies, be it in shooters or story driven adventure games, and whatever Dead Rising is. But as an RTS opponent, they seem off to me. Just my personal opinion, though.

I was never a fan of zombies in general. I think a post apocalyptic setting is a lot more effective without any outside threat at all. You don't need zombies to make humans behave like primitive assholes.

Let me throw in "Oxygen not included" as a great alternative for a steampunk post apocalyptic RTS.

What's up?.

It definitely feels hard. Like I've had to be careful in where I place all my Tesla towers for extending my build radius, as well as keeping them out of reach of the infected.

Whatever you do, don't attack those "doomed" cities, as they contain hives of undead that will go straight for your base.

Soldiers can kill infected easily, but their guns create a lot of noise. Archers are great for scouting and picking off undead laying about, and their arrows are silent and their mobility faster than the soldier class. 

Automatically taken less seriously for the use of the moniker "Dark Souls of ____". Just say it's hard, man.

It's easy to just read the rest of the OP, rather than hedging all bets on the last part of the title alone. besides, it's already been mentioned before, it really doesn't need to be mentioned again as it takes things off topic entirely.