Thanks for the feedback! I actually did think about adding power ups, but at the end I decided not to add it, though I might later. I thought about something that "upgrades" some of your pieces, but only by 1 "rank" etc. Not sure why I really decided not to add them. I might have thought that it might make it too complicated. I might add them in the better version (as an option). The falling tiles actually look more interesting, and I am pretty sure I will add them as an option to the better version. Thanks for the idea.
By the way, I played your game and it's really cool, and the art is amazing and so cute :)