A simple, yet nice code to add some touch to the gameplay. Especially hard and kaizo hacks might profit from this patch.
As for bugs and unintended exploits, you still can spin underwater but because water disables spin jumping altogether. Doesn't break though it might be good to add a water flag check in the next update. Switching the jump during the goal march animation also works, although this one might be used for a goal trap.
Lastly, I removed all spin jump tags and replaced them with "abilities" but the code itself is unchanged.