This is a pretty good 1st game. The art is great, I wish there was audio. The controls were hard and it took me a while to understand that I have to shoot the sharks. So consider adding a tutorial (for example just 2 short texts explaining the controls, like : WASD to move , Space to shoot). The gameplay is simple and has potential to be expanded. The hitBox of the projectile could be a bit larger to make the game less punishing.
Overall, a very solid 1st game. Keep making games!