That's the app market for you Robin :( I only pointed to the free versions so no need to buy it if you don't want
I think such is the way with that industry, you spend a lot of time making it, it's no Angry Birds I would be the first to admit, but takes a lot of time and effort to do, and there is no pleasing everyone, as with most things! But the people who like it never tend to write reviews often!
People rate it 1 star and say "no sound" without realising it's THEIR phone that is on mute mode, but yet never come back to rate it once they work it out (if they do or even read the description where I remind them to ensure it's not in silent mode!)
...Think of it a bit like Tripadvisor!
A great example is the Duplo app, it's free, no advertising, yet gets hammered with a fair few 1 star reviews, yet my little boy loves it, and I think it's a great app and would happily pay for it!