At the bottom of the guide in the "Bomb Alchemy Paths" section, it lists bombs alchemy paths to a certain category.
In "The Vortex Bombs" section, should there be an alchemy line for the Obsidian Crusher? Since it's a different vortex bomb that deals shadow damage similar to the "Graviton Vortex" but also has the chance to poison foes. It's the only bomb I really see missing from this section.
Obsidian Crusher was listed earlier in the guide, but editors neglected to add it to that alchemy path thing you're describing. So I just added it.