The spider looks cool and the music is pretty epic! I didn't understand how to catch the flies though, they didn't come close enough at first. Later I figured out how to catch them, but even after eating the flies, the game just ended and said: "Enemies: 0". I'd also increase the spiders range!
Maybe I did it wrong, but hopefully this feedback can help you improve the game in the future :)
Anyway, interesting idea!