Hello, I tried dragging fire but the little green goblins still came and attacked the tower. Maybe their health is supposed to decrease.

This is a really cool game!  I love the various gestures.  I know it's still under development, but here are some suggestions for you:

• The enemies should come a little faster.  It's a bit too easy right now.
• Maybe there could be a mana pool you spend with each spell, that slowly regenerates.  Then you could have mana regen upgrades, too.
• The little purple wizard is adorable, but he should do a "casting" pose (arms/staff raised?) every time you cast a spell, so it looks like he's doing something.
• Maybe don't cast fire unless you're actually dragging on the road.  That way, when I do the "Thunder" gesture, it doesn't also do fire.

Overall though it's really a great start.  Can't wait to see it develop more!