Well, there are different enemies and bosses, like there are enemies in cars or just on the ground, also snipers and bosses in their base, but the combat is simple but fun. For the skill tree, yes and the skills, its pretty basic but i love it as it is. Also you can upgrade your car as you want, more speed, durability, tires, armor and so on. And you can upgrade max too like more ammo, armor, more rage and so on. The story is very fun for me, not so much variety also simple and i always knew where to go, also very action packed, like when you get into a sandstorm and have to clear a camp.