I’ve played the first two levels and I can qualify it as fun. One thing that bugs me about it, though, is the constant changing of the camera angle. I don’t think it’ll happen as frequently on an iPad as it does on an iPhone, but it is annyoying nonetheless. Also, it is not available (yet?) on the Mac.
One interesting thing about Spyder: it’s the first Arcade game to get a gameplay video on Apple’s YouTube channel.