Portable mechassault? Yes. Good idea? Read on...
Now, no matter what rumors you've heard, the game still has action out the wazoo, and (once you find your control scheme) it works great. For those of you who use the stylus, take heed that you might need to lift it up every now and then to recallibrate the screen. The game includes tank combat, the battle armor (now in smaller doses), pilot form (kind of cool, although this game still lacks any weapon for it except for the pilot bomb), and the series base of mech combat. All of it is fast paced, and while it is challenging, you will better your adversaries through perseverance. The only complaint is that the graphics aren't pleasing. They are reminiscent of the PS1 games, but since this is the DS, they are accepatable. The characters and mechs look impressive, and the tanks look ok. As for game length, this will last you for a while.
For a departure from traditional platforms onto the DS, these guys took a risk. Now, is it worth it? That's for you to decide, but I think it is.