Nice idea and a good start
The graphics are decent, the music and sound effects are unobtrusive. However, once you begin to create a line/web I noticed that the spider retracts if you release the controls. This would be great in case you made a mistake, but it does not actually cancel line creation. You are stuck in place, unable to move along the walls, until you correct the problem by actually finishing the line. The retraction then seems a little rhetorical, while a nice visual touch.
However, over and above all, you need to take a look into the Pause functionality, as it appears to not work at all. I had paused the game just when a new level loaded, before given the Go, to multitask. I then heard the sound of being killed and came back to see the spider falling off the screen behind the pause 'window'. Additionally, I noticed the timer still running. I unpaused the game, thinking perhaps it was a bug in pausing when I did, but pausing the game once more netted the same result. The timer ran and eventually an insect killed my last spider.
In so doing, a message telling me 'Failed' began to cascade down the screen over and over and over, a game over 'window' popped up above the pause 'window', and the entire Flash locked up forcing a page refresh.
Aside from that, it's far better than anything I could create, so good work!