It is hard to describe how good Call of Duty 4 is to someone who has not played it. It is a near perfect realization of what Infinity Ward has been trying to do with the COD franchise ever since it's conception. It continues to deliver the same fantastic single player gameplay found in the first 3 titles, but it adds a revolutionary online mode. The major changes in the online have less to do with gameplay, and instead focus on achievement and advancement. As you play online you gain experience which lets you increase in level, the higher you get the more guns, attachments, challenges, and features you unlock. But what really makes this addicting is the rate at which you progress online. This isn't something you need to play for years to advance in, with just a few hours of play a night you will be getting constant advancement. New weapons, new attachments, and new awards. If you get to the maximum level, you have the option to trade in all your levels for prestige, in the form of a special icon next to your name, and reset to level 1. You can do this prestige mode up to 10 times for 10 different unique icons. In the end, while COD4 has a great single player mode, along with plenty of content on that front, it is the amazingly addictive online mode that will keep it in your machine for months to come. The graphics are good looking, while still maintaining that COD style, the sound is amazing as usual, with great 5.1 support. Overall, if you are looking to buy a FPS COD4 should be at the top of your list, it has one of the best online modes ever featured in a shooter, and a great single player campaign.