Hey congrats on your very first jam! It's a really big accomplishment, definitely take the time to enjoy the post-jam hype. Now on to your game: it was fun! I really like the style. The flooded forest idea is pretty cool and the unique colors of the trees with the vibrant blue water makes for a pretty neat palette. The audio, while not too fancy, did its job.
The boss was fun to fight and the game felt good. I do feel like the dash maybe covered too much distance to where it was harder for me to estimate where I'd land. So I actually ended up beating the boss without the dash at all, which added some nice challenge to it. I do feel like the ranged attack is a little too useful. So maybe if the player didn't have a dash they could spend a bit of their stamina by using the ranged attack. But I'm not here to tell you how to design your own game.
The design is overall really good! While I think the relevance to the theme could have been a bit stronger, the game itself was quite fun. Keep up the good work!