your plants are not getting enough light so they are stretching either the light to far away or its not adequete to use for growing.
would probably just try again when your sure your lighting is sufficient.
although you have a leaf problem you shouldnt be to concerned about it now, looks like fertilizer burn from starting to use fertilizer to early or possibly a soil that has to much fertilizer to really be used for seedlings, but your leaf problem may have not even occured had the plant received sufficient light.