Firstly, the patterns are not random like the other piano tiles games. Each song has a set tile pattern. This includes the color of the tile. Every repeat, you will see the same exact tile in the same exact column. You can try to remember them and see how it goes, but with experience in the other games, its pretty easy to just watch and adapt.

Secondly, you can earn 30 coins in almost every song. Each song costs 30 coins. Thus, you need to complete a song to get another. Out of the 50-70 songs I have so far, only 1 had 28 coins, and only 1 required multiple play-throughs (completing Wave 3 multiple times) to obtain all 30 coins.

Thirdly, the tiles sometimes overlap. It is annoying in some cases, but in most it is a generally familiar pattern (especially when you do it multiple times), and doesn't cause too much of an issue. This also allows you to see the tiles on screen for longer, meaning a higher speed can be achieved without as much reaction time needed. (since you can fit up to 12-16 tiles on the screen at once compared to 4-8. thus 12tps is actually traveling down the screen around half the speed making it much easier to tap.)

Hopefully this helps :)