(TAS) Sonic the Hedgehog Genesis (Genesis) in 12:40.50

Zip zoom, motherf***ers! It's summer!
Sonic the Hedgehog Genesis (Genesis) is a hack of the original Sonic the Hedgehog for the Sega Genesis/Mega Drive by Xenowhirl. Made in 2006, the hack features physics modifications that attempt to recreate the buggy physics from Sonic the Hedgehog Genesis (GBA), a Game Boy Advance port of Sonic the Hedgehog for the Sega Genesis/Mega Drive.

Star Light Zone Act 3's boss is one of the hardest parts to TAS in my opinion because not only do you have to hit the boss right after his invincibility is gone you also have to launch the spiky balls quickly before it misses the boss and you lose a lot of time. It's almost frame perfect and you need to know the right time to land the first hit on him after the slope jump.

Sonic the Hedgehog Genesis (Genesis) has quite a few features ported from Sonic the Hedgehog Genesis (GBA). According to SonicRetro:
It has background effects.
It has bug fixes, such as the Caterkiller-damage bug, scrolling-left-too-fast bug, and die-during-level-resize bugs.
It applies a left boundary teleport fix, signpost art loading and collision fix, skippable score countdown, "walking jump" fix, momentum preservation, "press start" fix and edits, altered rebound physics, altered jump physics, etc.
Boss physics have been altered; the player can bounce on bosses until they are defeated but their invincibility times have been changed from 0.5 seconds to 1 second.
Sonic's sprite art and the life counter text are replaced with the different art from Sonic the Hedgehog Genesis (GBA).
The scrolling is changed to give a better sense of speed and Sonic CD-style look-ahead.
All springs double Sonic's max speed until landing if airborne before the spring counter runs out. All side-facing red springs act like yellow springs. To compensate for the lower speed, slope repel calculations aren't performed after hitting a spring. Vertical springs erase all horizontal velocity not in a direction being pressed.

However:
Zipping through walls is much slower due to the modified physics.
The slowdown and pop-in from Sonic the Hedgehog Genesis (GBA) are not present.
Landing on steeply curved ground still acts much like the original Sonic the Hedgehog and sometimes conflicts with the momentum preservation.
Sonic the Hedgehog Genesis (GBA) has Sonic starting off Green Hill Zone Act 1 at a location further to the left.
Rising platforms in Green Hill Zone are not solid.
The dynamic level resizing is not changed.
The switch under the monitor in Labyrinth Zone needs to be removed.
The momentum preservation against upside-down spikes is not changed.
The first Buzz Bomber does not fly high enough.
The music should continue playing and not restart after losing a life.
The music is not remixed.
There is no game save function.

You can download the ROM from SonicRetro below:
http://info.sonicretro.org/Sonic_the_Hedgehog_Genesis_(Genesis)

I think I lost a few seconds on Star Light Zone Act 3...

Timestamps:
0:00 Gam Start
0:08 Green Hill Zone Act 1
0:35 Green Hill Zone Act 2
1:00 Green Hill Zone Act 3
1:47 Marble Zone Act 1
2:08 Marble Zone Act 2
2:47 Marble Zone Act 3/Boss
3:39 Spring Yard Zone Act 1
4:25 Spring Yard Zone Act 2
5:01 Spring Yard Zone Act 3/Boss
6:09 Labyrinth Zone Act 1
6:39 - Labyrinth Zone Act 2
7:33 - Labyrinth Zone Act 3/Boss
8:38 - Star Light Zone Act 1
9:08 - Star Light Zone Act 2
9:33 - Star Light Zone Act 3
10:18 - Scrap Brain Zone Act 1
10:59 - Scrap Brain Zone Act 2
11:46 - Scrap Brain Zone Act 3
12:05 - Final Zone

https://discord.io/BahnDaten