Some friendly advice first: Don't assume that just because you start off with a Russian assault Rifle (AEK 971) therefore you must be on the Russian team. I wasted quite a few minutes trying to capture a base wondering why the Stars and Stripes Flag refused to change to the Russian Tricolour.
This is the first Battlefield game I have played although I immediately recognised many similarities to Frontlines Fuel of War. which was I believe based on a mod for an earlier incarnation of Battlefield. Frontlines is a pretty good game but despite the backing of Microsoft it never managed to gather the critical mass of customers that is needed for a multi-player game. Happily Bad Compnay 2 has sold very well and with ongoing developer support has carved out an important place for itself in the pantheon of on-line shooters.
For those others who have never played this type of game the basic structure comprises of large maps with two teams competing for control. Players select one of four classes (Assault: a general soldier, Engineer: who excels at fixing and destroying vehicles , Medic: a healer who carries a light machine gun and Recon: the games sniper). A wide variety of wheeled, tracked and flying vehicles are available to commandeer so typical battles feature fighting on multiple levels.
Compared to Call of Duty / Modern Warfare style games the maps are bigger, the teams are bigger and there is far more emphasis on achieving team objectives rather than personal achievements. There doesn't seem to be any non team based game modes. There is a progression system in the game that allows you to unlock new weapons and abilities as you level up. While you get some experience from individual kills you seem to get more from team based activities like capturing points and supporting your colleagues with healing and ammunition. There is also a generous bonus for being on the winning team. This emphasis on team play does make the game accessible to weaker players (like me) who can still make positive contributions to the team even if they have a lousy kill to death ratio.
Not that there isn't plenty of room for skill in Battlefield. I imagine than a team of organised skillful players could launch a devastating co-ordinated assault encompassing foot soldiers, vehicles and air support. You don't see this on the casual servers I play of course. I usually find myself on a team of twenty uncoordinated players many of whom are running around doing their own thing. Happily the game has a squad system where you are given the option to join a squad of four players. In the disorganised chaos of pick up games you can achieve a lot with a squad of four players who are prepared to stick together. Even if you get lumped with three completely uncoordinated players it is still worth being in a squad because you can spawn beside any of your squad mates after death. This is a brilliant innovation in my opinion. Not only does it save you the long trudge back to the front lines but it also gently encourages squads to stick together.
Overall this is a very enjoyable shooter, one that I hope to play a lot more of. My biggest gripe is the unnecessarily steep learning curve required to get into multi-player (hence my gaff described in the first paragraph). The entire single player campaign really doesn't teach you more than how to move and shoot which most players know how to do already. With multiple classes, multiple game modes and a variety of weapons and vehicles to learn the multi player game could really use some kind of tutorial. This complaint is not unique to Battlefield. I have yet to encounter a multi-player shooter with an adequate tutorial although Team Fortress 2 makes some concession in offering an optional training video before each map. Back in the bad old days of Quake and Unreal you could at least play the game with bots before your exposed yourself to the challenge of human opposition but it should be possible to do better now with today's big budget multi-player shooters and offer a proper tutorial.