Just noticed that the main entrance and exit of the Scarlet Hillside isn't marked with a red star. Don't recall seeing that anywhere else.
Also, while the spirits of Silverwood exploit has been mostly fixed, you can still make them invisible on the first screen if you warp to them without picking up the eye. Could probably be fixed by warping the player to an intermediary screen if they don't have the eye and forcing them to pick it up there before warping them to the Spirits of Silverwood. But it's hardly a big deal.
Edit: If you go to the Valley of Rust to save Gustav's Lion and glide far enough to the right, you skip the auto-save that's meant to happen before the evil wizards.