Played it, it is slightly fun, but does not have a lot in it yet. You have some stiff competition from other aggiepeople when it comes to this genre.
Here is what I would do: You have a cute and simple skybox perspective with some pretty small enemies and characters, use this perspective to create a more unique experience. Really big enemies, not big sprites but perhaps made out of multiple parts, a spider or ant comes to mind. They can be simple looking but have complex movement instead.
Big ass enemy bosses, earth defense force style.
Otherwise perhaps go full wizardry, cooking your own spells, making potions or something like that.
Or both.