Give it a chance, it's a non-ordinary game
When you purchase the full version, you have access to the "gallery" (levels A to G).
This game is based on perspective camera and sometimes a tricky use of the holes (black and white), you can control the camera with the analog or with the pad. The design of the levels is quite good, although most levels use a trick to get all the echoes.
You can also get access to network levels (a to r ) that is just levels designed for users, some are a piece of cake (I think they did them just to get the trophy), but the most are complex.
Speaking of trophies, you can get all of them in an easy way, just keep playing this game, there's no hidden trophies or a "difficult".
Sometimes the camera control is frustrating, regardless if you use the analog or the pad, and when you pause the game, if you press X to return to game, you are restarting the level (you have to press O). This sounds weird, but it happens to me like 4 times, so be aware of this.
If you're a fan of platforms or puzzles, this game is a MUST HAVE in your collection, or if you just want to play a different genre this is your option too.