Sonic The Hedgehog 2 development theory.
So, there is still some debate on this topic, I will say what I think it would of been like if it was finished. This does contain some information that we know of.
A early conpect was indeed time travel. This was uncovered May of 2017.
As you can see, time travel worked differently than in Sonic CD. ===Zones (Simon Wai/beta zones. In level order.)===
Green Hill Zone
- Is a early version of Emerald Hill.
Neo Green Hill Zone
- Is a early version of Aquatic Ruin.
- One of the beta zones.
- Has a wooden maze theme.
- Boss is called Saw Eggman.
Casino Night Zone
- Has a pink card art style.
Hill Top Zone
- Not much of a change.
Mystic Cave Zone
- Not much change.
Dust Hill Zone
- It is a desert level with some underground sections.
Oil Ocean Zone
- Has a rolling ball gimmick.
- Has only 2 acts.
Cyber City Zone/ Genocide City Zone
- Became Metropolis Zone Act 3 in the final.
Sky Chase and Wing Fortress
- Almost no changes
Death Egg Zone
- Has 3 acts, the first 2 being what became Chemical Plant Zone, and the 3rd act is the final game's Death Egg Zone.