This is very well done. I like the twist on tower defense. I don't have a lot to say beyond what has been said in other comments. I got to Day 6 and my browser threw up an error and the game froze, so I didn't get very far. Regarding the gameplay juice feedback you asked for:
- I like how impactful the combat feels. I'm not a fan of the circular area of effect that the attack has. I didn't feel like there was any major skill to combat; I just ran to proximity of enemies and spammed attack without regard for positioning.
- I'd have liked a bit more enemy variety. In the 6 days I played, I only ever saw that one chipmunk looking guy. I don't know how long the game is, but having a new enemy type thrown in on day 2 or 3 might make things a bit more interesting.
Amazing job on the graphics by the way. It's really a beautiful game. I found myself just flitting around the swamp admiring how everything looks.