It's unusually addictive, but still buggy
And the penalty for dieing is not so harsh.
This is a good start. You have the formula for an addictive defense game.
But it's just not fair for the demons to have all this freedom of movement and you don't. They have more effect on your world and your limitations that you can handle.
Sure you can rebuild but the idea that you can't stop all the destruction is meaningless. Especially those exploding stars.
You need to figure out a way to enable players to ensure a good round against the unpredictable. Like a talisman that banishes all evil. A fail safe.