And it is addicting. There are plenty of unit variety and commander powers for each faction. You pick several units from your arsenal to deploy into battle. Unit composition is important! Every wave sends out your units automatically. You can sell the units for half price and buy a different unit as you study the enemy's composition. And you regularly unlock new units as you level up, which is awesome, unlike other free-to-play fare. You do not pay for every wave's units, just when you buy said unit initially.
All the units, and future unlocks, are balanced against each other. For example, you can opt to unlock and use snipers instead of a rifleman. A sniper is not necessarily a lot better than a rifleman, as it just has a longer range and slower shot, but it fills the mass infantry slot. Each unlock is simply a variation of an existing unit with a special ability and a different, balanced weakness. There is no pay-to-win, a low level player can win against a higher level player.
The thing that makes the game great is that there are hard counters and a rhythm. Explosive suicide beetles do not work on shields, when they can usually make a mincemeat of your other units. Stealth detectors reveal cloaked enemies. Cloaked enemies can make short work of the tough units you have if you can't see them. You an either swarm many small units or save up for the big guns.
I only got to play the free-to-play Early Access/Open Beta version of the game. I would be playing it right now instead of writing this post if it wasn't for the Open Beta ending. It is that addictive.
Apparently, it was inspired by a Starcraft 2 mod called Desert Strike. The influence from Starcraft is definitely present. Three factions, one of them being the Terrans. The Atlac are Protoss. The Yaguiaoi or however you spell it is supposed to be the Zerg counterpart, but with a more zoo-like aesthetic.
The soul essence mine resource acquiring needs a bit of work. Resource gathering is a constant stream of increasing soul essence, which is fine. However, at higher waves, you need to upgrade said mine, which stops resource gathering for quite a bit. I was not a fan of holding off picking units which costs essence to upgrade mines. The resource gathering is passive except for those moments. I think resource gathering tied more to the game flow and play would be better.
As you destroy enemy units and crates, you gain some soul essence but mostly gold. Gold is used to be spent on commander powers such as bombing runs or special "epic" units.
One thing though, the menu music is terrible. Please, please change it. The cheery tone does not fit the game, except possibly ironically. I also would love to have the English translation done better. There are story lore still in Chinese(?) that needs to be translated.
Regardless to say, I'm waiting for the full release! I hope it still sticks to being free-to-play. Free-to-play actually works with this game, and I'm interested in how the developers will take Art of War: Red Tides.