One of the best platformers you'll ever come across, N is a great freeware game from Metanet that boasts excellent real-world physics - something we don't normally see in 2D sidescrollers.The plot: as a ninja trapped underground, you must escape with your life by getting to the exit on each level while avoiding a horde of homicidal robots.

Created entirely in Macromedia Flash, N sports minimalist yet very effective graphics, smooth and realistic movements, and excellent implementation of real-world physics including collision detection and gravity. The game is very difficult, though: there are hidden traps, and you have to constantly replenish "gold energy" to survive. In many levels, you need to climb walls and flip switches at the right moment. Like a real-life ninja, acrobatic feats and deft fingers are crucial to beating the game. To make things even more challenging, the robots seem to get more dangerous and smarter the more you play. Fortunately, elegant physics and fun level designs will keep you glued to the screen even if you curse the designers for making such an impossible game :)

Last but not least, the game includes extensive in-game help and a built-in level editor. With 150 levels organized into 30 unlockable 'episodes,' the official release will keep you occupied for days, if not months. The latest version also now saves your progress as you play, making it much more appealing to beginners (including yours truly) who got far too frustrated with the first release. If you are looking for a charming, innovative, and very challenging platformers, look no further than this modern-day classic. Two thumbs up, way up!