Using savestates

First load the game itself (ROM). Then choose "load savestate" from one of the menus in the emulator.

 

The high-pitched sound usually means you were not using the correct ROM...
Are you loading Sonic 2 Final? The glitchy HPZ savestate is meant for Sonic 2 Final, not Beta.

 

Press Shift+F8, select the file and press Open.

Be sure you've loaded the right Sonic ROM first.

 

Make a save state with Sonic 2 Final (Press F5 in Gens 2.11)

Then download my Sonic Scenario Tool, load Hidden Palace, and then open the save state (F8 in Gens 2.11)

Here is my Sonic Scenario Tool:
http://chaos-emerald.virtualave.net/sthscene.zip

With Sonic Scenario, you can unlock almost every scene in Sonic 1 to Sonic & Knuckles without playing the game. Good?

 

Step 1: Open up Gens 2.11

Step 2: Open Sonic 2 Final

Step 3: Press F6 a few times until it says: "Slot 0"

Step 4: Press F5 at any time to save the state

Step 5: Press ESC (The screen will go blue) Don't close Gens!

Step 6: Open Sonic Scenario

Step 7: Select "File" on the menu and "Open Save State..."

Step 8: Open the file that has the same name as your Sonic 2 Final ROM, except for the ending, it shall have the ending: GS0. E.g: SONIC2.GS0

Step 9: Press "Yes"

Step 10: Select "Zone" under the Scenario border

Step 11: Select the zone: "Hidden Palace Act 1" in the select act box

Step 12: Press the"Close" button to save

Step 13: Back in Gens, press ESC to get rid of the blue color

Step 14: Press F8 to load Hidden Palace

14 easy steps :P

 

It's a ratio button/option button. A little circle you press inside and it get checked.

It says "Zone" and not "zone" btw.

 

Just do as this screenshot and it will work

 

Try to press ESC.

If it doesn't work, then I cannot help you

 

You can select debug mode with the Scenario Tool. Then you don't have to let Sonic fall and die

 

That's because the level was removed. The pointer to the level is still there, and when it's loading up the level, it takes some random trash from Oil Ocean Zone.