Interesting concept, that weapons/characters have different ranges and that you have to strategize your next attack. Difficulty ramps up very quickly. I think I did well on my first try:
Nice work on the game. As for improvements, I'd personally work on a bit more feedback on retrieving characters, maybe that you gain them once you step on the tile.
Aside from that, having a way for the player to pace the tempo of the game might be the most significant change. So everything updates once the player does an input action. (Maybe this already happens? But there is some delay on it) Tailoring the game speed to the user.