Not all its cracked up to be
From the grainy graphics to the akward control scheme this game not only fails as a first person shooter but lacks the nostalgia of the original metroid side scrollers.
I was very unsure about the control scheme when I bought it, and although its better than I thought it still just doesn't function as a FPS.
Graphically the DS just cant quite support this game. Most of the enemies you will kill just look like small polygonal things buzzing around the screen. You cant really tell what they are... It very much reminds me of shooters I played on my mac back in '95. (thats not a compliment). The boss fights are also repetitive and kind of bland.
For old school fans the exploration and puzzle solving to navigate throughout the world is still there, but not in the right way. Your scan visor tells you just about everything and each little world thign is very small.
If you are looking for a FPS on the DS, look elseware. If you are looking for some metroid nostalgia, look elseware. Online play is ok but it doesn't make up for much.
Althought a nice attempt by nintendo if you want shooters in a handheld you need to get a PSP and if you want the old schoolness get the advance games.