There is a full walkthrough available on the GameFaqs board. http://boards.gamefaqs.com/gfaqs/gentopic.php?board=562603When you get there click FAQs & Guides to get to the page with the walkthrough. The guy has put sections, so if you don't want spoilers on level names don't go there. If you don't mind that but don't want other spoilers, just search for the section names he lists to jump to the bit you are stuck on.I have only read part of it, but it looks quite well written and comprehensive.

Also available since November 7th on IGN.http://faqs.ign.com/articles/665/665079p1.html

I was horribly stuck on Devil's Island - kept on getting crushed in the spike trap before the waves. This helped immensely! It's well written & pretty comprehensive - well worth a look if any section's got you bamboozled.

This is no help whatsoever. I have no idea where I'm supposed to spray the weed killer in the Air Filled Tunnels

There's a door in Esther's Lab that takes you right above the Prison area. The place to spray the Weed Killer is directly to your right as the tunnel widens into the Prison second level. Also, straight in front of you, there is a spiral path down to reclaim your booty.

Here is a link to what I consider the best walkthrough for CoCDCotE:http://www.gamefaqs.com/console/ps2/file/928161/39789