I like it! Fun and small, which is what game jams games are all about!
For pixel art, I have a couple tips that really helped me out!
I notice that your art uses a lot of different colors. One of my favorite things about creating pixel art is its restrictions - early video games had access to very limited color palettes and had to make the most out of very few colors. But by using lots of different shades, you can really blur the lines between realistic and retro. Your artstyle is very cartoonish in design, but is shaded realistically in other ways. Your one-color flag for example, very much contrasts the realistic shading of the main character.
Color design is one of the toughest things to nail in pixel art - so I generally let other people figure that out! I highly recommend using palettes from lospec.com, it's an easy way to have color synergy without knowing what you're doing. Using a palette is a great way to have uniformity in your art.
You have some anti-aliasing on the borders of the tree sprite. This makes the trees look like they are blending together with the sky background. I generally prefer to use anti-aliasing in art that doesn't move much - like static portraits. (here's a guide to what I'm referencing: https://medium.com/pixel-grimoire/how-to-start-making-pixel-art-4-ff4bfcd2d085)
If you haven't already stumbled across this, let me hand you the bible of pixel art: this blog is created by the guy who did all the art for Celeste - this is the perfect reference for creating pixel art and animations! I swear by this website, it is my favorite bookmark.