Maybe too difficult?

I love this game. Exactly what I wanted. Only problem Ive seen is maybe earning upgrade points is a little too difficult. Im on about the 30th level and I cant pass it, nor can I upgrade my towers because upgrade points are so hard to earn. Maybe make it easier to upgrade towers (upgrading from the map screen, not in-battle upgrades).

Derping Bacon Boss about Toy Defense Fantasy — TD Tower, v1.23