Prototype Zones/Emerald Hill
From Sonic Retro
Green Hill Zone
Nick Arcade Prototype
As with Simon Wai's prototype, Emerald Hill is the most complete Zone in the ROM. It's the only one that can actually be completed, and it's the only zone with a boss. (Of course, we're not counting Green Hill Zone.)
Act 1
The first thing you notice when you play this zone (by pressing start or by selecting it from the level select) is that Tails is missing. Emerald Hill is the only zone in the ROM that does this. If this is indeed the Nick Arcade prototype, Tails was likely disabled to prevent him from interfering with the 25 ring challenge.
Different spinposts!
Emerald Hill Zone Act 1: Final
Emerald Hill Zone Act 1: Nick Arcade Prototype
While there are plenty of layout differences between this prototype later builds, the entire Act still feels very familiar.
Note the similarity between prototype B's layout and the layout seen in the Nick Arcade video:
Act 2
More of the same.
This is one fundamental diffence in the layout, a spring takes you into one of the paths inside the wall.
Interestingly (though not visible in this static image) is the circles in the background pulse quicker than in the later versions, this happens in Act 1 as well.
Like in the later prototype, Robotnik comes straight down from the ceiling.
However, unlike in the later prototype, he explodes when you beat him! In Simon Wai's version his wheels simply fly off without any explosions. Note, however, that the explosion graphics are from Sonic 1. It seems that at some point between Prototype B and Prototype A, the old explosion graphics were removed without being replaced with new ones.
And thats the end of the playable part of the game!
Emerald Hill Zone Act 2: Final
Emerald Hill Zone Act 2: Nick Arcade Prototype
Some minor differences dotted around this act, mostly in the middle.
Simon Wai Prototype
Emerald Hill Zone was, quite reasonably, known as Green Hill Zone in the development stage. This zone is mostly completed. GHZ is also the only zone in this prototype that has a boss.
Act 1
This snail enemy, which didn't make into the final game, is everywhere in GHZ. He charges towards Sonic once he's seen.
GHZ is littered with dead-ended tunnels. For example, this tunnel is supposed to lead you to a 1-up within a waterfall.
Cycle through the debug objects, and you'll find this high-tech looking star post.
Act 2
Another dead-ended tunnel. Still, you can get the shield using debug fly-through.
Robotnik landing on his vehicle. There's no chopper sound, and he comes straight down instead of flying horizontally from the right. Interestingly, the boss music is deeper and much slower.
At the 7th hit, Robotnik fires the drill, as usual. Sometimes Tails glitches and is able to walk in air diagonally, as shown here.
When defeated, Robotnik doesn't get burnt. His vehicle doesn't explode either, it just disassembles.
Then the supposedly missing Sega logo comes up! It's believed that the pirates have hacked the ROM to prevent the Sega logo from showing up as the game boots.
Here's another glitch. Try fighting the boss with a shield, Sonic's sprite will quickly flicker through a set of weird objects.
