Hey, your art is fine for a short gamejam game, especially as you are just starting out how to make games. That's how we learn! Pretty decent all across the board, you have all the makings of a game here, and it's actually playable, which is still a great achievement. You can actually say you have made a game!
I'm giving you decent marks, and I hope you continue to make stuff, because it's only up and better from here.