i like the concept but when the bat falls and you want to dodge something quickly by flying down and then back up, it takes too long to react. the bat falls up or down too fast & even clicking wont get you back up in time to survive.

It's flappy bird,right?
Why black bat die when collide with black spider or black pumpkin? It's wrong because they are from one team. Create main hero and enemies different visually and logically.
Sure default GUI is ugly.

A bit too simplistic, but a good start. The flight (vertical) is too slow compared to horizontal movement. The menu can look better and more personalised for this game. The score needs to be shown after you die. It could also use some instructions, showing which enemies to avoid (especially if you're planning on putting in power-ups).
Like I said, it's a good start. I'll try to come check it out again.

It's a good idea, although I think it's really hard to play and it has bugs like, sometimes, I star flying so high that I lose or sometimes batty wouldn't fly even if I try really hard.