Sonic 2 Dev - Revised Level Order

With more development materials released by Hirokazu Yasuhara,
the planning of Sonic has become more clear.
Not perfectly clear yet, but with all the maps accounted for,
and the full timeline sheet, along with more sketches,
I have pieced together a revised zone order:


Present:
1 Emerald Hill グリーン
2 Ocean Wind オーシャン
3 Secret Forest/Woods ウッド
4 Sandy Shower サンド
5 Metropolis メトロポリス


Middle Ages:
6 Tropical Sun トロピカルサン
7 Blue Ocean ブルーオーシャン
8 Mountain Madness?


Ruined Present:
9 Rock World ロック
10 Oil Ocean オイル
11 Dust Hill ダスト
12 Death Egg デスエッグ


Ancient:
13 Hill Top ヒルトップ
14 Blue ブルー


Future:
15 Casino Night カジノ
16 Chemical Plant ケミカル
17 Genocide City ジェノサイド
18 Neo Death Egg ネオデスエッグ
19 Space 宇宙


There are discrepancies between the timeline sheet and the maps.
With emphasis on the timeline sheet, the maps paint a different picture.
The maps show more zones in an era than the sheet says exist.
This could mean that the zone labels don't neccessarily reflect level order.
For instance, with Hill Top labelled in the Middle ages and Ancient maps,
they may have been labelled to highlight where the region had moved to.
The same could be said for Rock World Zone, with its region existing across eras,
but only being a playable zone, as Rock World, in the Ruined Present.

The middle ages were difficult to place, but Blue Lake seemed to fit,
as did the recently unveiled Fortress level in a Hill Top setting (Madness Mt.)