Not that good cause

its old and casual

Well...

It's not anything really new or original. You did ok though.
Only thing you added as your own touch was clicking on the spider, but meh... it's not really one of those great touches of uniqueness.
So it's basically a game you would only play for a short while. And i don't think it would get anyone really hooked on it.

My advice:
Add some music. Having some cool music in the background would be helpful. But try to make it long, or change. When it's only one short music clip looped over and over you end up just wanting to mute it. (Add a mute option too, just in case ;) )

I also had an error when i got the score. Which was, i didn't get a score. I played in Normal to try it out. And when i beat it it said my score was: And there was simply no number showing my score, it was empty.

Anyways. You still did pretty good for it being your first flash game ;). So You get a 3/5 and 6/10 from me ;).
Cheers keep improving! ^_^