First things first, let me say something nice about this game. I genuinely like the vehicle designs. The tanks and armor are merely serviceable, but the airships are a neat sci-fantasy design, and the ironclads have some real amazing detail on them. So, that's one unironic and unreservedly positive thing I have to say about the game.
Now, let me complain about it a bit. It has Steam achievements, but they are broken. They apparently worked when the game was launched, and after it was patched, but some time in the past two years, the Steam client was updated, and the achievement system broke and was never fixed. It's not a huge deal, but it would be nice to have some intermediate goals to help me fill out the 20 hours.
My other complaint: WHY ARE THE MAPS SO HUGE?! Trying to get across on foot takes forever, and even in a vehicle, the time you spend traveling outnumbers the time you spend fighting by, like, four-to-one. The only way to play as infantry is to observe the map from the overhead view, wait until your troops engage in battle (in deathmatch mode, they always slit up as they run out of the spawn point) and jump into a character while they are fighting the enemy. Then, if you're me, and not especially good at shooters, you almost immediately die while blasting randomly at the air around your targets. And, of course, the 1860s weapons are mostly awful. The standard issue rifle has to reload after every shot, which means that someone as inaccurate as myself will basically hit nothing before dying to enemy fire. It's quite frustrating.
I have, however, found a way to play this game that is moderately fun. Basically, jumping into infantry is a non-starter, because of the aforementioned control problems, and also because the map is so huge relative to the character (plus the enemy is pretty thin on the ground - my theory is that the maps are to scale with the real battlefields they're based off of, but instead of having 170,000 people present, there are only 24). Yet, playing as a vehicle in deathmatch mode is not particularly rewarding, because nothing is a threat to you. The computer will not use them.
However, there is another game mode - Army Skirmish. That is the RTS game mode, where you can issue orders to your troops. It's not a very good mode. The units' low movement rate and the large map size makes your forces very tactically inflexible, and because of the fog of war, by the time you notice the enemy, it is much too late to actually do anything about. Also, many of the orders (such as the basic "attack enemy" command) don't work. So, trying to play it as an RTS is a waste of time.
On the other hand, in Army Skirmish mode, the computer will control vehicles. So, by fielding a squad composed of a single tank, and then directly controlling it, skirmish mode becomes an ersatz tank-based shooter. Enemies are still far enough between that it's not particularly satisfying (there is an "army size" option when you start skirmish mode, but it appears to neither limit the size of your squad nor cause the enemy to field a bigger one) - but it is a passably playable experience.
With the sound turned off, I can listen to a podcast while playing, and, while it will never be my favorite pastime, it is reasonably diverting. I suppose that's not too bad.