Well, what can I say? Take every element of lbp2 and port it over to the vita. As well as all of the brilliant features that made lbp2 a success, lbp vita has a few tricks up it's own sleeve- such as touchscreen(and rear touch pad)support, individual level saves (enabling the community to create 10 hour RPG's) and a completely new story mode.
The story mode is only really used as a way to unlock items for use in create mode. It lacks any depth, and at certain points is very unclear what is happening. Personally, I completed the story in only 6 hours, and the only vaguely challenging aspects were the boss fights. Thankfully, the dull campaign is saved by it's staggering replay value, I found myself playing levels over and over again to get that one extra score bubble to boost my record.
When I first booted this up, I was pleasantly surprised at how much it looked like lbp2, if not better. The same bright, cheerful style has been maintained throughout the lbp franchise, making any lbp game instantly identifiable.
Some "hardcore" gamers complain about the 'floaty' jump mechanics, but I struggle to see what the issue is, all I want to do is gather that last prize bubble and boost my multipliers.
Literately, EVERYTHING in lbp is customisable. From your pod (basically the menu) to your moon and Earth (where you create and share everything).
The lbp community, is often described as the most creative, and in the past 2 weeks I've seen this, as over 20,000 levels have been published.
Finally, a game that would make you want to actually BUY a vita. There are hardly any flaws with this game and therefore, I highly recommend it.