It is. They don't take very long at all before you start blowing stuff up, either. And boy is it satisfying to do so. What's funny is that I now know where the difficulty of the game lies. Not that I'm saying it starts off difficult, but I kind of realized where you can truly hurt yourself. It's your wallet. You are given some good cash, but if you make too many wrong decisions, it'll cost you dearly. Things are expensive, and you have many decisions to make on what ordinance is best for you and at the time. Choose poorly, and you'll waste a lot of money (and actually come out of missions with less than you started with); choose wisely, and you make money.
This becomes more apparent when you face various structures and vehicles that require a certain level of ordinance in order to punch through the armor, etc. (eg. If you got a light machine gun, don't even think you'll level a building with it, or even penetrate most large armored vehicles). This can leave you in a situation where you may have to abandon a mission because you lack the money and resources to finish an objective. Then you would have to find a mission, that you can complete, to get money back again. This hasn't happened to me, yet; but already once, it almost did happen.
The destruction is of MechAssault 2 levels, but certain places do tend to rebuild over time. What does change is how the theatre of war changes. So, the building might be rebuilt, but if you originally blew up the building while doing a job for a certain faction (like removing the original occupants); you may see that the place is now occupied by that faction.
There's various groups fighting and attacking each other while you do your thing. It's up to you who you help or do you just ignore it? Just be warned. If you are on the ground, and you start to see mad unfriendly air support fly or drop in, you might want to vacate the area. You might be able to call in carpet bombs and mortars, but so can they. I'm not sure they can do it as randomly as you do. Normally if things are raining from above, you can find the source of it.
