When he was 1.5 has it then changed abruptly. He knew at that time almost all the animal noises, but with 1.5 it has to perceive these cubes until properly targeted and above can use self-correct.
With a few months, he has only ever tried draufzuklopfen and then of course, did not the noise ... 1.5 he has been able to as I said only really deal with it.
He is now 2.5 and now plays the part for over a year (and football). I can truly say that the cube is almost indestructible. The sounds still work, batteries I've also not have to change !!!
The sounds are a matter of taste - I personally like them quite well - my son also. Recently, he can even recite the rhymes and finds pretty funny.
Overall, the money has been worthwhile to spend so - albeit a little later than expected :)