A fantastic game with an exhilarating campaign that is only beaten by it's highly addictive and rewarding online play.
It has three game modes: campaign, online, and special ops.
If you try to play online the game will suggest you play campaign first. You don't have to but playing a bit of campaign really gives you an idea about the entirely new strategy elements this game has brought to the genre. The game starts 5 years after the events of call of duty 4. The game gives you a short training course on the mechanics of the game then shoots you into the combat. During the campaign the game changes between a few different people. This can get confusing but it creates huge plot twists that really draw you in. This game is also very original in the way that it makes you switch up your strategy. If you keep attacking every enemy with the same strategy you will die. Fast. The game doesn't let you kill all the enemies from the same spot, usually. It makes you run around and it constantly keeps you on your feet.
The plot itself cannot be more enjoyable. Although it lags at points when your tasks are small, like at one point it tells you the absolute worst has happened to the world and then it transports you to a small town that your supposed to save. It throws off the plot a bit but as the plot thickens it draws you in further then any other game of it's time. The climax out does all the other call of duty games and any other game I've seen. If you value plot at all in a game you must get this game.
The online is also great. It has quite a few different and unique maps. It lets you make your own class with weapons and things you unlocked online by leveling up. There are 70 levels in all. ranging from private to major and goes on up above that. When you pass 70 you go back to level 1 but you get a prestige star. to signify you passed 70 once. Every time you pass 70 you get another one. You don't lose your emblems or tags either when you get a prestige. So you may not have all your cool weapons after you pass 70 but people will still know your hot stuff.
The game also brings back kill streaks. Which allows you to get new and very powerful toys after a certain amount of kills in a row. Like if you kill 8 people in a row without dying you get a helicopter that flies above for a short time and kills anyone it see's. Or if you manage to get 25 kills without dying, which does happen occasionally, you get a nuke. It ends the game and your team wins. That comes in very handy, if you can get it.
Leveling up is a pretty simple process. You find a game and you get experience. How you get experience and how much you get depends on the mode your playing. Team death match gives 50 per kill and 100 per head shot. Search and destroy gives 500 per kill or for detonating or defusing the bomb. It should be noted that you get more experience in it because you don't have any lives if you die.
Special ops is a completely new mode to the game. It has 25 different levels but you need to unlock most of them. You start out with 5 levels you can play through and by doing well in those you unlock stars which unlock 5 more. And then you have to do well in those 10 levels to get 5 more so you have 15 total levels. This repeats till you have all 25. The levels take place in places you played through on campaign, but they feature different enemies and sometimes different scenery and always a different objective. Most of the levels are either time trials or survival. in time trial you just have to get somewhere or kill enough people in some amount of time. In survival You have to survive 3-5 waves of oncoming troops. Do that and you win. On time trials it matters on how fast you go to decide how many stars you get. On survival you have to choose the level of difficulty before hand and if you survive that level you get whatever amount of stars was elected to your difficulty.
All in all this is one of my favorite games of all time. If you like shooters or any type of game at all I would recommend this game for you.