The graphics form a cohesive whole and I like the flight feeling of the bat, a bit less the flight pattern of the birds that made me drop on them like a rock and fly back up quickly instead of chasing them around (edit: just read the help section, the dash helps not dropping like a rock a little :)).
It's well done and I liked playing it, even if my personal record is only wave 6 :)
I ended up using wine on linux to play the window version instead of installing love2d