Don't get me wrong this game is awesome. Visually stunning and the new features are exciting such as new underwater missions and improved interactivity. But anybody who has played Dark Mirror will be left somewhat dissapointed by the depth of the storyline and how short it actually is.
There are not as many missions in Logans Shadow compared to Dark Mirror and this I personally think that this is the major reason that it is underpriced, afterall it is a good game much more fun than Splinter Cell.
The major disappointment of Logans Shadow is the Multiplayer. Anyone new to the series will be calling me all sorts of names right now. But there is no longer a ranking system where you gain bonuses such as new weapons or increased health for higher ranks and the XP system is pointless and doesnt always work. Also if to many people are playing or there are several explosions the game lags and frame rates decrease causing some psps to crash. However the actual missions and map of the multiplayer are brilliant and a great improvement on Dark Mirror.
All in all it is an absolutely amazing game however does not beat Dark Mirror to be fair no game as of yet has come close to beating Dark Mirror. Still a very good game don't get me wrong.