Decent review that really sums up the game. I'm not sure I was too fond of the omission of scoring as well. The game will track stuff like "combinations" (I think this being how many marble clearing moves you can make in a row) but, again, without a score I fail to see any point in doing this.
Something, however, that I DO think this game has over the many other Zuma (marbles on a track shooters) is the whole "Amulet System". Kind of like a simplified version of what they already did in Azkend and Dragon Portal where you can choose not so much a power-up but more like a certain game rule tweak to be in effect the whole level by which of the 15 amulets you choose to wear. While some of these effects seem a bit more useful than others, I appreciate how the game tries to balance some effects that might be too "game breaking" (making stuff too easy) with some built in disadvantages as well. Like an Amulet that slows the progress of the pieces down a little but at the same time makes them much smaller and therefore a bit tougher to precisely target. This also means that amulets unlocked later in the game are necessarily "better", just different.