Simple concept been done a fair bit before. Actually quite enjoyed not dying horribly for slightly clipping an object, although a way to reverse/back-pedal in a dead end would be useful.
Simple game with nice graphics and a simple gameplay. I also like the music.
Maybe you should write "Maintain left click to flap up/Release to flap down" or something like that I good english (I'm not sure what I've written is good). Also explain the use of the flies and the cages could be usefull.
Nothing else to say... it's nice and simple, but I only repeat myself. ^^
This is one of these games which players either like or hate immediately. Even the music is like this, so it's a real bet. Must reassure you : in my case, I found it interesting. Only thing is that controls request practice and I tend to not see the walls coming in time so I simply crash on them before seeing what's coming.