although COD 4 for DS can feel like a shooting gallery sometimes, it still plays a mean game of warfare.

User Rating: 7.5 | Call of Duty 4: Modern Warfare DS
Distant gunfire can be heard over the nerve-tingling music as you sprint up to the corner of the dusty middle-eastern street. you draw a breath, step out of cover, and you come face-to-face with a scarf-wearing terrorist with an AK...who is only capable of standing rooted to the spot while firing bursts of gunfire with one-second intervals.

That´s what COD 4 DS can feel like. You´ll be immersing yourself in the war-torn, gritty world it portrays, only for a painfully obvious flaw to pop up and stomp on the atmosphere.
These flaws range from general graphical lack of polish to the players god-like ability to seemingly reverse time by back-tracking through the stage.
The latter can have especially disastrous consequences, as you trigger set pieces again by passing through the triggers. Objectives you have already completed are given to you again, enemies return to life like zombies, and scripted explosions go off a second time.

Sure, the game is very breakable, but you kind of have to be nice to the game and just try to avoid the flaws, and it can get tiring to constantly have to play the game in a way which does not show to many of its flaws. For example if you hide behind cover where the enemies can´t hit you, they will stand and fire bursts with the same intervals of about a second.
Ratatat. Ratatat. Ratatat. Ratatat. The only thing breaking up this is the enemy occasionally chucking grenades at you, and those are easily avoidable. The enemy soldiers never attempt to storm your position to take you out, they just wait patiently for you to pop out of cover. This problem basically means you have to create the intensity yourself.

Now, with the technical problems out of the way I can tell you what Call of Duty 4 for DS does well. First of all, the visuals, especially character models, look good. There are also a decent amount of guns in the game, although only a few are very efficient, luckily you´re never stuck with the crap hardware for long, as SMG´s are quickly thrown away in favor of assault rifles.

the missions, though few, are varied and sometimes very immersive. You´ll have a good time blasting terrorists in the face in locales ranging from russia to a tanker ship to the run-of-the-mill middle east warzone. The game never get´s boring, and the plot, while unimpressive compared with home-console COD 4, is quite engaging.
All in all, if you want an FPS for DS, this is a good alternative, it won´t last you longer than 10 hours, the multiplayer is nothing speciall, and there are technical flaws, but you will enjoy your tour of duty here.