The intro was kinda nice, but that's it basically. The game's much too short and much too easy. There's no need for the upgrades, but you don't even have time for collecting money anyway, because you can beat any level in the first try without problems (the last level requires 22000 feet and I had 40000 without even paying real attention to the game and only very few upgrades). Also it's much too monotonous. There's nothing new, only a bear, rockets and rocks. The only thing that changes is the background. It's not enough to keep this entertaining, I'd say.
Didn't like the art style as well, but that's rather some personal taste thing, I guess.