N+ began life as a free downloadable Flash game on the PC, introducing gamers to a small ninja-like character who avoids hazards while flicking switches and working his way through countless levels. Now the game is available as an Xbox Live Arcade download, and even though it costs 800 points, the equivalent of $10, it's more than worth it. This is one of the best games for the service, period.
Your goal in N+ is to go through each level, locating a switch to open a door and then returning to that door unharmed while collecting gold pieces to keep a time limit from expiring. It starts out easily enough with "point A to point B" levels, but complexity heads north with unreachable ledges, mines that explode on contact and various other hazards, including missile launchers and robot sentries. Your ninja character dies after just one hit and can't survive long falls. This makes the game relatively challenging, but not impossible.