We all know why you got this game, there's no need to pretend.
It delivers on its promise indeed, less than 30 minutes should be more than enough for you to get your shiny Platinum Trophy, which is what you expect from a Ratalika game.
The game is actually fun, the graphics are super simple as well as the sound but it fits perfectly, I think the game responds quite well and it offers enough variety (and challenge later on) to be entertaining.
If you go straight to the plat then it'll be a fun 30 minutes, if you wish to keep playing for a while after, is a fun game to have on your PS Vita in particular while traveling.
I'll give it 4/5 since it delivers on its promise, but let's face it, it was a very small promise.