The Amazon slot machine was launched in 2016. They are one of the many casinos (and bingo rooms) on the Jumpman Gaming network. They are still relatively new, so there is not much information on them online.
I did find some comments about them. However, most of these comments are ambiguous - obviously they have nothing to say about Amazon Slots. But this did not prevent them from bringing the highest score to Amazon Slots. This is not to say that they shouldn't get them - just when I find information about them online or feedback is rare, I find it difficult to give the casino the highest score.