The thing is that as well as the different game modes and different settings, Combat Arms includes ranks, the more experience you gain, the higher your rank, and this will give you access to more and better equipment. But you don't only need experience for better equipment. Depending on how well you play, the games your team wins and your role in those victories, you'll be rewarded with virtual money with which you will be able to rent (yes, rent) weapons and equipment. In Combat Arms, the equipment is rented for a specific amount of time, after that time, if you haven't gained enough money to rent it again, you will have to use the basic weapons and accessories.
There are dozens of weapons available for all the different gaming styles, from guns to sniper rifles, and forget about carrying an enormous arsenal, because the more you carry, the slower you will move. It is all thought and developed to be as realistic as addictive.
This tactic is very good to get the players hooked, and furthermore, they'll be able to see themselves in the world ranking, which is frequently updated. So, download Combat Arms, design your own soldier and start fighting.