Call of Duty: Modern Warfare 3 is a bombastic, technically accomplished first-person shooter for home consoles, so you may imagine that a translation of that experience to a seven-year-old piece of hardware with basic 3D processing and no analogue sticks, would be a rough one.
Not so, as Defiance manages to capture the spirit of its inspiration and provides a solid FPS that captures the spirit of its big brother, albeit with some tweaks to the formula that may turn off veterans of the series.
The reason it works well at all is that this is a side story to the campaign seen in Modern Warfare 3 proper, giving the developer a tone and setting to work with while at the same time excusing it from the high intensity action of the console versions.
The DS hardware simply isn't up to that challenge, so n-Space wisely sets much of its action in tight, drab environments to keep the animation smooth and somewhat excuse the murky textures.
Defiance isn't always a success in this regard. The framerate drops dramatically when the screen gets crowded with enemy soldiers. Models run awkwardly and physics are unconvincing at best, but the gameplay goes a long way to make up for this.