You'll have to excuse my inner Sonic fan for this post because there are just so many problems from every single standpoint that it honestly disappoints me.
First off.
This is not Hidden Palace Zone.
This area:
Does NOT look like this area:
Hidden Palace Zone for one, would be
hidden and I don't just mean "lol lets place it in GFZ1 for a secret everyone will know and have access to". Hidden Palace was placed under the ground simply because of fact that it was a hidden palace the deceased citizens of the island kept to themselves to guard from outer world threats. You know, kinda like how in SA1/SADX Eggman shot a LASER to the ALTER SHRINE (Which should be the real name of this level).
On top of that, look at the location of that shrine, what do you see? I don't see water at all. Now you could say this is based on the past version of the shrine, except there is another issue already noticeable in your own version.
Why are there houses on Angel Island? Why is the sky old THZ1? If it's based on the past version why is there any sign of actual industrial civilization when Angel Island was supposed to be in the sky back when the original tribes reigned on the island?
I'm sorry but trying to make it feel special by making your own version of GFZ that adds the entrance to your level, only to have access to an emerald that doesn't do anything at all, is NOT a good enough reason to consider this location a worthwhile visit in ANY scenario besides the one thing you appear to have obviously made it for. You tried to respect the legacies of the "original" Alter Shrine, which is fine, but when you have so much incorrect that the only value in the map's identity is your attempt at making an 8th emerald appear in the game, I'm sorry, but you HAVE to do better than that.
Can we seriously get a second look on maps with no real "goal" in mind when the map, despite it's efforts, has literally nothing of true replayable value in it besides just being a hangout map, like there needs to be an actual tag besides it that lets other players know that it wasn't really meant for the "get to the goal/clear this objective" type of level expectations.