When you buy sound shapes off the store, you also get a copy of the game for your given console (So buy PS3 get Vita as well, Buy Vita get PS3 as well).
I remembered on Motor storm RC if you got trophies on one console you would automatically get them on the other due to the cloud save system. Sound shapes does this as well, only you have a choice this time since the cloud save is only optional.
I wonder if this will keep happening for any game where you get both versions in one purchase.
Still doesn't stop this from being a very good game though, if not a bit short.
Edit: Since someone mentioned it, you do need to own both the PS3 and Vita to do this since you do need to sync up the cloud save data to unlock the trophies, meaning you will need to at least load the game on both systems (It's a cheap way of getting trophy hunters to buy both Vita and PS3).