This game has an exciting concept of a war vehicle in all 3 elements: air, sea, and land. The game offers a wide range of vehicles and multiple factions to choose from.
Why is the review negative? This game is very grindy and repetitive. You really have to devote yourself to this game to make any significant progress. If you enjoy grinding, you might like the game, but I personally don't.
This game, in my opinion, is only fun with friends; even then, you sometimes get burned out quite fast. Sometimes you would even stay in 1 vehicle for a couple of hours or even days!
Given these points, I would not recommend this game unless you enjoy this type of research grinding. Though the Gameplay may be fun to a certain extent, I don't feel it's worth the grind. One thing to be noted is that this is my own opinion and a subject to change.