A while ago, while reviewing FPS games, I mentioned a free online FPS called Combat Arms. Well I stopped playing that due to the various hackers and lack of variation of gameplay, and went on to bigger and better things (EVE, WoW, and the Total War series). Well, while I was waiting for a patch for Call of Duty 5 to download, I decided to pop in and see what the game was like after a few months of production (it was relatively new when I was playing it). I was suprised at what I saw.
First, I was skeptical, because their webpage had zombies all over it. However, having played their new Quarantine maps, I must say it's hilariously fun. Essentially, you have a team of players, and one is randomly selected to be infected. They become a zombie with three times the health of an ordinary player. If they hit you, you become infected as well. It is a wonderful game type, because in the half dozen or so I've played, everyone groups up in two or three person groups, but heads for the most defensible area. Inevitably, three or so people get infected rapidly, and it turns into a King of the Hill match with zombies trying to storm the humans and infect at least a couple of them. I have yet to see a game where the zombies didn't win, which may imply more tweaking is needed. Still it is a hilariously fun match type.
Also added is a "Fireteam" mode. While there is only one map for this, it is essentially a player team vs a computer scenario (similar to co-op modes in most FPSs). The team must complete objectives in a limited time, with health and casualties respawning when they reach certain spots. The game is challenging on hard, and ridiculous on extreme, but you may get an item out of succesfully completing the mission.
They have also added a good handful of new weapons, new armor, specialist skins that can be purchased which give you bonuses and penalites, and a "black market" where different things can be bought (such as the ability to change your gender).
They have also eliminated a good deal of the hacking, or at least it appears they have. I haven't noticed any blatant hackers, and not anything that couldn't be explained by people having some measure of skill (although, considering I lead a couple games after not playing for this long, skill may not be as prevalent as I think). They have improved the old matches with new maps (including a very close quarters map called Death Room), and all in all have made the game more solid.
The GP system remains, and can be tedious if you just want to relax. Enemies will inevitably have better guns than you, and its best to just stick to the basics if you only want to play casually. I get a G36E and body armor, which probably costs a total of 1-2k of gp for the day, which is easily earned back with an hour or two of fun.
You can, however, also buy items with real money. While I wish they didn't add this option, it is still an option, and if you really want to waste your money on that, why not buy a real fps?
Now to speak about what remains the same.