I like the idea and controls. The different enemies are cool and it was a fun game to play.
Critic: Like others already said, a warning before the attack of enemy birds would have been cool. And of course it is a pity that you had not enough time for sounds and music. Try to get a flow for effects, It would have taken less than an hour to record implement basic soundeffects if you know how...I made mine on the last day too ;)