This game has ridiculously over priced items.
It also has a mean strategy of allowing you to play only against opponents that are stronger than you to force you to keep upgrading.
Additionally even if you kept buying there is no guarantee that you will get what you "exactly" want because of a system called crates in which you buy a crate not an item or an upgrade and what is in the crate depends on your luck. Only few offers are with fixed known items in it, and those are highly priced even for this game scale.
So to have a good account you need to pay thousands of dollars and every week there is new over powered units that you have to buy to keep winning !
Additionally F2P are just fodders for P2W they can't even give them a good run for their money.
Furthermore, there is no actual PVP battles you just compete against other accounts and the game AI moves your opponent unit so you technically playing against a zombie.
There is no wonder that game has only 1 star rating.