Few things that should be implemented:
1) Speed button.
2) More number. I mean, like the Grow Spell, how much atk, def, size will it raise?
3) Mini Map.
Bugs noticed:
1) If you keep retreating and pushing forward your hero you can atk way faster than his normal atk spd.
2) If your "Goblin Limit" is full and you cast a summoning spell, you'll lose that summoned unit.