I agree with everything applestar said, [including that I'm not seeing cobwebby stuff], but I would add that when you look at the picture enlarged, some of these look like classic examples of damping off, with some browning and constriction of the base of the stem just above the soil line. Damping off is a fungal condition that young seedlings are very vulnerable to in conditions of too much moisture and not enough air circulation.
It can't be cured, only prevented. The prevention is just what applestar mentioned, make sure your potting mix is well draining, doesn't hold too much moisture, don't over water, add a fan for air circulation. I have found that it helps to add A LITTLE bit of cinnamon (like a pinch in a pitcher of water) to the water you water with. Cinnamon is a natural anti-fungal.
And yes, way too crowded and spindly, like not enough light. Check out the seed starting basics thread at the top of the seed starting section.