N+ is an enhanced version of the game N, originally a flash based browser game. Players control a small, but very agile ninja through different small areas. Next to movement, only a single button is used to jump, but this allows the ninja to run up walls, do wall jumps and cross large distances.
Levels are divided over different episodes unlocked gradually. Each level consists of a single screen with a time limit. The amount of time can be replenished by collecting golden coins, but the main goals is to activate the exit, usually by touching a specific button or opening a number of doors. Areas are filled with hazards such as spikes and droids that shoot laser or rockets. There are also obstacles such as platforms that only move in a single direction or falling damage from high platforms. Death is always instant, but the player is given an unlimited amount of tries.
The PSP version includes a mix of original levels and user-created ones with about 200 in total. There is also a level editor and unlike the Xbox 360 version these can be shared with other players. The PSP version shows the levels from a "medium" distance, while the DS version contains a far view and a close view on the screens. Physics are also slightly different in each version.
There are both competitive and cooperative game modes available in multiplayer sessions. Players can switch between the pure mode with original graphics and the plus mode with enhanced visuals. The unlockables includes victory screens, new music and new colours for the ninja.