Alright, I needed to come back and properly leave a comment this time.
First of all, the art in the intro is amazing. Hand made nice drawings telling the story, superb! And the music gives it a very nice ambience.
The gameplay while simple is fun. You have a some different towers to build. It's a bit chaotic and keeps you engaged all the time because if you stop for a moment you are done.
I found the game a bit difficult, I was a bit overwhelmed by the hordes at some point. They started destroying my towers and I couldn't keep up.
Also, one thing I would improve would be the fire animations of some towers. The one that creates explosions block a big chunk of the screen and that makes you get a bit lost with what's there. You don't know if there are enemies or if you character is being attacked, etc.
The menu with the three options is nice, you can easily navigate through your weapons, the tower build and the type of towers. About the towers, I would have radically changed the design in the selection menu and I would have let the player maybe stop the game while looking at the screen to think about the strategy. There is a pause menu, which I found out just now, but it blocks the view.
It's a very good game, no bugs that I have seen, building options, autogenerated hordes of enemies, movable character so you don't get bored by just building so you can actively fight, great graphics in the intro. Very nice game!