Game is anything, but casual
Under colourful veneer lies one of most RNG dependent Popcap game. It might look easy and relaxing at first, but it is one of the most intense game you can find. On the last levels, there is no room for error, but because how RNG works in this game, most of your runs are destined to fail. Power ups do not spawn. Wrong power ups. Power ups spawn, but ball does not. Ball has an autistic tendency to be spawn the same, especially when you have nowhere to put it. You will often find yourself in situation where you are close to losing and game decides to spawn balls which you do not need or even can’t place them. One green ball at the end of the chain which you can’t reach? 4 GREEN BALLS IN THE ROW! In a similar matter lines are being spawned. Sometimes they come in long mono coloured lines, in other times they are mixed with only few balls to pop.
Game at the highest level is all about RNG. There is something fundamentally wrong mechanically in game when you can almost double Ace time in this game and still have not a slightest idea why you lost. Sometimes you make mistakes and win, other times it is hopeless from the very start. Game does not leave you time to think, to play with smash mechanic to reverse flow of the balls. It is all about speed at which you can perform and hope for the best that game does not decide to screw you.
Another issue is that there is no way to come back in this game. If balls roll almost into the mouth, any other ball is likely to push them into it and you lose. This means that you can’t fix your situation after a certain point.
In conclusion
In might be good for nostalgia trip, but there is a reason why nobody had copied this formula and it is because game is frustrating when you play it a lot. Half of my playtime is in two last levels. I played for 4 hours in 12 1-4 levels. It is very frustrating experience when you ramp up difficulty, you should just quit when game gets hard, because otherwise it will just ruin any good impression this game had.