Developer: Team Ninja
Publisher: Tecmo
Genre: Action
Sub-Genre: Adventure
Release Date: Jul 3rd, 2007
Additonal Info:
Developer: Deep Silver
Publisher: Deep Silver
Genre: Action
Sub-Genre: N/A
Release Date: Q2 2009
Additonal Info: Also available on PC and Xbo...
Developer: Ubisoft Montreal
Publisher: Ubisfot
Genre: Action
Sub-Genre: Adventure
Release Date: TBA 2008
Additonal Info: N/A
Played through every nook and cranny of the Ninja Gaiden Sigma demo multiple times? Looks like it's been more worthwhile than you know. Continuing to impress, Team Ninja and Tecmo have announced a way to extend the life of the currently released NGS demo.
When players buy the final game in retail disc form, it'll be able to detect the amount of the demo you've played through and appropriately award you. What will the reward be for playing through the same incredible level over and over you ask? You'll net a handful of Yellow Essence, that handy form of in-game currency that both purchases items and can power up Ryu's arsenal. This will surely make the final playthrough a tad easier for all you crazies who attempt to play through it on hard (though, even normal is a challenge in Ninja Gaiden).
So while you should have already downloaded the brilliant Ninja Gaiden Sigma demo weeks ago, now there's even more reason to check it out.

Ninja Gaiden Sigma Exclusive Trailer