The intro is legendary!
The controls could have been better chosen. The R and F buttons are located in very impractical locations, and the space button (the most accessible button) is almost useless. The escape button causes the game to shut down (or crash?) which is not a very enjoyable experience.
I found most bonuses to be useless. The main problem is that the AoEs are way too tiny, and I couldn't make them land where I needed them.
Falling out of the bridge causes you to be stuck forever.
The enemies often spawn 10cm away from the player.
When the enemies are close to you, it's almost impossible to tell when you get hit. The sound design is really good, it would have been nice to also have a sound effect when the player is being hit. An actual health bar could also make the game a lot easier to play.