For your first game, it's pretty good. The background makes me a bit dizzy after a while though lol
I like how you can move with the arrow keys, some games only make you move with either WASD or the arrow keys but not both. So I like that you implemented both so players can use their preferred controls. I think you should add that to your description though so other players would know.
Also I think it would be better to have space to shoot instead of the left mouse button since there is no need to aim. That way, all the controls would be oriented to the keyboard and it would allow players to play this with just one hand if they use WASD and space.