This game is very beautiful!
It has 2 modes - single player or competition (against the AI). Single player can become boring very fast, because all you do is eat a certain amount of food (orbs) to finish the stage. Competition mode is fun because the AI actually challenges you and you can only go to the next stage if you win against the AI. But it also can become boring very fast, which didn't happen to me considering the game only has 14 stages and 2 of them are specifics to get achievements.
The controls are easy enough most of the time. It can be a little frustrating depending on the evolution of your spark, but easy to manage.
The game leads you to believe that your spark will evolve in different ways based on the type of food (orbs) you eat. That's not true. Not only the evolution of your spark is the same no matter what you eat, but you can't actually choose what to eat (not in competition mode at least, since you gotta beat the AI). You can choose what to eat in single player (the game only requires you to eat the necessary amount of food of at least one color), but it makes no difference whatsoever.
The game is not worth the full price, but for 90% off I say go for it. You get trading cards and 22 achievements in a few hours. I didn't regret buying it. I suggest you watch a video of the gameplay though, just to be sure.