So this game isn't assassins creed portable, its assassins creed, all of it.
It doesn't have some of the features from the full console version, however it doesn't feel like a portable version.
It has free roam (the first proper free roam game on the Vita).
It has hidden blades, swords and guns.
It has weapon upgrades.
It has costume changes.
You can own tailors and blacksmiths.
It has a great story.
Everything you want from an assassins creed game it has. The graphics are by no means as good as its console counterpart,however they are still very good graphics and when the gameplay immerses you this much it doesn't matter.
Quite simply if you own a Vita, you need this game.