A complete disaster when compared with the original.
Granted, this game does include all the same enemies and weapons, and they even got a graphics upgrade! BUT WHERE ARE THEY?! Before I finally quit playing this game all together--around level 20-ish--I had only seen probably four or five enemies that weren't those spheres that just mindlessly move around the level on a set track. It seems to me that when they were designing the levels for N+, they were playing a constant game of "How Many Mines Will Fit?". There's no running from missiles, dodging machine-gun fire, or ducking under lasers. N+ merely forces to player to make frustratingly difficult precision jumps between a countless number of mines, from one side of the level to another, with the occasional switch in between to unlock a door. SNORE.
PLOT/STORY: Simple: You are a Ninja, and you need all those little gold pieces to survive. So go get em! And don't die along the way. Very basic, yet quite entertaining.
GRAPHICS: There's not really much to say about the graphics. It's a simple 2D sidescrolling game. They upgraded the look of the gold pieces to appear more 3D and shiny, as well as the enemies (or lack thereof), but that's about it. Oh, there's also the newly-added option to change the color of your Ninja. Joy.
MUSIC/SOUND: The music isn't too bad, actually. It's sort of a fast-paced electronica/techno type beat, similar to LUMINES. The sound effects are exactly the same as before, as far as I can tell. Again, the quality has probably been upgraded or changed for the PSP port, but there aren't many sounds to work with anyway. The sound of your Ninja's bones crushing from a fall seem less gruesome, however, as does the squishy blood splatter. Probably done so they could give the game an E rating.
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The Ups: You play as a Ninja. That's pretty nifty.
The Downs: Terrible level development resulting in frustrating (sometimes boring) gameplay; lack of innovation; dummed down for the kids.
The Bottom Line: I wish I still had that $14 to buy myself something more useful, like cyanide.