Okay, after playing a few rounds here is my initial review:
Combat Arms is sort of the poor mans 'CoD4' lots of liberties have been taken by Nexon to recreate that environment in a modest fashion and to a degree that's ok, albeit very very very hokey. The graphics will remind you of the early Quake days and dont require a lot if any heavy graphics support to run the game which could be good for some users. The fighting system is A LOT like War Rock (another free to play fps) with weapons that must be 'rented' from a shop using in game money you obtain by killing enemies during rounds. More guns become available as you level up and new customization options open up as well. I played with a few different guns and didnt notice any real difference in the way they fired or their accuracy.
Your going to want to go into options and set the controls up CoD4 style because it took me forever to figure out how to throw a grenade and the rest of the controls are pretty poorly mapped default. The actual game is very cheesy and hokey feeling and is more of a 'run and gun' setup than anything tactical or skill worthy. My first three games I placed 2nd, 1st, and 1st on my team with a gap of about 7 kills between me and the previous player except the last game where a guy was on my tail the whole time.
The most positive thing I noticed were that the levels I played were a lot of fun. Lots of places to hide at and lots of places to sneak up on people while they were looking out windows or crouching behind crates. The levels dont redeem a lot for the poor graphics but it did make me want to play a second and third time.
So in closing I give it a 4 out of 10 based on these parameters:
Graphics- 3 of 10 (The doritoes I ate earlier were a strong enough chip to run this maxed, lots of 'floating' bodies after they die and dont bother sneaking around corners because your gun pokes through the wall)
Sound- 2 out of 10 (No music, minimal gun fire sound effects)
Playability- 6 out of 10 (It is fun for a mindless run and gun game, but coming from CoD4 that wore off pretty quick)
Challenge- 4 out of 10 (Im hardly awesome at FPS and had no time getting a pretty demanding lead in my second two games)
Price- 10 out of 10 (Its freaking free and worth downloading to kill some time, you likely wont invest much time in it in the long run though)
Final thoughts:
If you cant run CoD4 or dont have the cash, this will hold you over till your ship comes in. Otherwise, stick to CoD4 because your really not missing out on anything.