This is a really cool entry! I really like that it's a turn based game, and you've got some good juice with it! The attack sound effect sounds good, hovering over units gives them a nice highlight with HP info, I really like a lot of the polish that's here. The pixel art is really fun as well, the red sword person reminds me of a Final Fantasy Red Mage and that made me smile.
If you plan on improving this game, two things I'd take a look at are some tutorials and moving the player units.
Tutorials are tough to get in during a jam, but once you get your mechanics locked in try and get one in there! I didn't realize the game was turn based until nothing was happening after the build phase, I didn't notice the end turn button.
Unit movement I'd try and make it if a unit doesn't use all their movement, you can click on them again to move once more. I accidentally moved my units too short, and wished I could fix it. I was also unclear how far the bow could attack from so moving that unit was awkward. I think these two things alone might make the biggest improvement to the game.
Amazing job!