Golds take more damage when rusted. A rusted Gold can be killed with a single blunderbuss shot at close range, while un-rusted will need another shot to finish it off (from any weapon)
Grass skeletons are resistant to guns
Shadow skeletons move faster than other variants
Honestly? I appreciate the effort, but this is a pretty bare-bones guide (no pun intended). It doesn't even differentiate between groups of skeletons armed with swords vs groups of skeletons armed with guns, 60 hp vs 100 hp, etc. "Slash, dash or gunshot to the face will be fine" will NOT be fine against a group of 8 skeletons armed with pistols. Not even the generic type. You'll get gunned down before you can get close enough to do any of those things. Nor does it cover advanced tactics. Sure, it tells you what their weaknesses are, but offers little to nothing on how to utilize those mechanics. No mention of parking your ship nearby for quick access to the ammo chest and/or cannons. No tips on how to deal with Grass in the rain, or Gold located far inland.
The website is designed pretty well, aesthetically speaking, but there needs to be more information. It's not so much a guide as it is an introductory brochure. I'm not saying that to be mean, like I said I do appreciate the effort. And not for nothing, but I never realized the environmental lighting (torches, bonfires, etc) worked on the Shadows. So kudos for teaching me that.