Game has no ending, just sends you right back to the intro screen upon winning, the upgrades tend to hurt you as much as they help you, with jumping leaving you vulnerable in the air for longer as you upgrade and dashing pushing the game to unplayable speeds.
The dinosaurs that chase you are pretty much a countdown until you lose a life, so you must kill them and later in the game you are forced to buy the level 3 gun to even have a chance when two start chasing you at the same time.
Overall it's an okay game, congratulations on making a decent looking game, keep on shining.