I will be Honest, at first i thought this game is going to be Boring, but i dont know what is the deal with this, maybe the artstyle or maybe the engine, that just got me, i am really enjoying it, it is early acces, there are some things to polish though, i like it anyways.
I still dont know how do you unlock them but i have a theory, and Im afraid of it, you must buy the units.. I mean, you have to unlock them with somekind of points or currency, maybe with real money, this is just a theory and i really hope to be wrong.
https://youtu.be/8YhmjN6olLk
https://youtu.be/RD7t9OPpvu4