[quote name='corrosivefrost']If the demo is done right, it can be a good representation of a majority of the game.
Demo for Ninja Gaiden Sigma? Good. They gave you the first level, some adjustable difficulty levels, a few missions in mission mode, some extra weapons to play with and ninpo to try out.
Demo for HS? (The US demo at least) Pretty much AIDS. You might get an OK idea of how the game plays, but when you get 3 minutes of combat, you can't really demo the combo system in any sort of detail.
Uncharted's demo was probably a pretty decent representation of the overall gameplay. And it gave you a decent amount of time with the game so you could experience it.[/quote]
Like the Ratchet demo, which is just the first level, but the rest of the game is standard Ratchet gameplay.