Very well done! This is an interesting concept: The idea of fighting a boss, but instead of actually damaging the boss, you dodge other entities that damage it, so getting hit yourself means you miss a hit on the boss. I don't think I've seen something like this before, very cool idea.
I also really loved the flavor text at the bottom. Short, quippy, and funny! I'm really glad you added a way to replenish health, that definitely helped given how much health the dino had.
You managed the space on the canvas really well too. The background fx, the news reel at the bottom, and the actual game contents were all readable despite the resolution restrictions. The only thing I might add is a little more 'juice' (maybe a little screenshake on the explosions when you or the dino is hit).
Great work!