4 stars: Takes quite a few upgrades every level, but can be achieved fairly quickly, if you're willing to watch the ads.
3 stars: Very addictive & fun, could be a great game. I paid to get rid of the ads as they are very annoying. Problem: Maxed out everything, boost & engine but now I'm stuck as the boost & engine of the plane reset at the start of a new level but I'm unable to increase them at it says they are maxed out. I think it's a bug! It would be 5 stars of they can fix this. Also could use a tutorial. It would save time.
2 stars: It's not a bad game. Yet it's really messed up that at the beginning of each round. Your boost, propeller speed, and earnings go back to rookie. When the cost of upgrading stays as high as a continuous increase in cost.
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