For a change, positive review! A hybrid between Battlefield and ARMA games (simillar to planetside in fact), concentrating on the realism and gameplay. In essence, it's a large sandbox with vechicles, both land and air (some of them huge, allowing transportation of other vechicles) and multiplayer. Unlike other reviews, I do believe that all the features mentioned in the game description are present.
However, the game needs some patience getting into. Much of it isn't exactly intuitive so you will need to do some learning and perhaps read the manual (GASPH). Like other games from this dev that I played, the game is heavily lacking in graphics however, being outdated and since kids nowdays don't care much beyond that...
With not many people playing it, multiplayer is rather lonely, or it was back when I played the game at least, so unless you have a bunch of friends, you won't see much of that.
Single player, it doesn't give you a 'corridor' to follow. It gives you a background, potential hints and leaves you in an open world. What you do is up to you. (Stop a disaster, or get the hell out and save your lives? Up to you)
To summise: If you are an older player who appreciates a game for what it allows you to do and not what it looks like, you will enjoy the open ended game where you indeed have as much a freedom as a game can allow. Even better if you have many friends who can enjoy it with you.
(For a taste of what you get on even larger scale, go to 3000AD page to download their 'Battlecruiser' games for free.)