ok after having done some 350,000 spins on one casino and about 200,000 on a second one, I can say I have a little bit of experience about this game.
I somehow like this game, I think it is a bit additive, since the game is designed to leave always at least one of the 4 achievements quite "close" to be reached. And when all 4 are at their beginning, the BOOST magically appears. Randomly.
Also, I think the MUSIC is ingenerating some kind of addition. Try to play this game with and without music. Two different beasts.
IMPO the TRTP is ok, as declared.
But I must agree with other players who complain since some symbols "disappear" when the player is close to reach an achievement. And the same symbols magically are more frequent on the reels when the player is far away from the achievement.
And this is something new, considering we are talking about a "slot machine". This is opening a new scenario about online slotting. I think that so far this aspect was a bit underrated.
Before this game release, we accepted the fact that DURING FREE SPINS the reels of a determined slot could be modified from the standard base game reels design. Take DoA, or many WMS slots. Plenty of examples. Still ok.
However, we still were in the situation of a ONLINE game which was visually representing a "mechanical" slot machine, I mean with 3,4,5,6...
n reels, and on each single reel there is a fixed strip/design of symbols.
Now, everything changes. We have a slot machine which is "self adjusting" the reels design in accordance with the players' achievements (I mean the "collect a thing" achievements).
This is no more a visual rapresentation of a "mechanic" slot machine since the above could be impossible to be done obviously. Visually, this is more a "movie" than a slot machine. In other words, the game is more a "scratch card" than a "slot machine".
RNG does nothing here.
This can be seen as a positive or negative aspect, I am not here to judge, but I think that whoever is playing such a game, has to accept this new approach, otherwise it could be quite frustrating.