Pretty relaxing and entertaining.
This is an awesome game. I love the concept, it's really unique and I think it would be hard to improve on. It's got a good element of challenge, enough to maintain interest, but not so much as to frustrate. It is really relaxing, and the music choice really helped with that.
As others have mentioned, I noticed the same bug where the game lags and then a huge portion of the web disappears, regardless of how many anchor lines you have spun. I've played about 30 spider deaths and in probably 25 of these were the result of that glitch obliterating my entire web. If this were not present, I'd instantly give it a full 10.
Advice for gameplaying:
A traditional centered orb web doesn't work as well as it theoretically would. The spacing gets too far apart toward the outer edge so the web is much too likely to break. It also costs a lot of thread to spin an effective full-sized orb web. The type of web I found to work best is to divide the upper two quadrants into two separate radial webs, then spin random threads from branch to branch between them. 4 anchors to the bottom was an effective buffer as well, especially if you make them cross twice.
Half of the usable area is more than enough insect supply to keep your spider alive and spinning. Anything more than half consumes too much time eating leaving none for building and your web will ultimately fail.
In the parts immediately after it saying "Level X" is the best time to rebuild your web as during this time it will be primarily flies, ladybugs and a few dragonflies. These are relatively harmeless and should mostly just be eaten for web provision.
In the part after the "Level X" when the forewarned insect or animal begins flying through is a bad time to build. If your web is built soundly, it'll be able to withstand the onslaught, leaving you to focus on eating queen bees and fireflies as these are what I found to be the most troublesome insects.
I recommend saving 1-2 of the stag beetles to use during your building phase. The risk to your web is worth it, and the gold thread works wonders patching the holes made by bees in the attack phase.
Keep in mind, triangles are the most compact shape. If you see any rectangular holes in your web, they are able to be bisected intro triangles which costs little web and greatly strengthens your web.
Once you don't see any spots that look addable to your web, during the build phase, drag lines all the way across your web, and chances are it'll fill in a few strands where you couldn't find any yourself.
Good luck, eat the bat. It's rewarding.