The Hidden Palace area of Sonic 2 is a cut stage that was brought back into the game in recent re-releases.
Debuting in the remastered mobile versions of the game, unlike other stages which appear in sequence, Hidden Palace Zone can only be found by discovering a particular route.
The stage appears again in 2022’s Sonic Origins, and while it’s not subject to any trophies or achievements, it’s well worth a visit for those who haven’t played the mobile versions.
If you’re trying to access it from the Sonic 2 level selector cheat, be aware that it must first access it normally – the next section explains how.
Where is the hidden palace area in Sonic 2?
To reach Hidden Palace Zone you have to play until you get to Mystic Cave Zone Act 2.
Play the level, with the route taking you along the bottom of the stage, until you come to a section with four angled fireflies – two of which are next to three rings in the air – followed by a closed bridge that you must open by jumping on a hanging switch.
The video above will show a route you can take to reach this point. Otherwise, the spot you are looking for will be the following:
Don’t jump on the switch! Instead, drop down into the pit. Instead of losing a life, you will appear in a new stage…
You will now start Hidden Palace Zone. It’s only a single act – but it comes with a unique Robotnik boss battle at the end – and once completed, you’ll start at the next stage after Mystic Cave Zone, Oil Ocean.
If you want to access the Hidden Palace area again in the future, know that you can use the Sonic 2 level selector cheat to jump straight into it. However, you will need to have visited the area by conventional means – i.e. the above method – before this is possible.