Sonic the Hedgehog (16-bit) (InstanceTopic, 19)

From Compile Worlds

The 16-bit version of Sonic the Hedgehog was the first game in the main Sonic series. It stars just Sonic himself and Dr. Eggman, and has a noticeable lack of spindash.

It also only had six Chaos Emeralds, so Sonic was not able to become Super Sonic in this game.

It had three acts per zone, unlike most of the games that followed it which would only have two. Sonic Advance 3 is notable for also having three acts per zone.

Because of its relatively simple programming as compared to later games, it has become the most hacked Sonic game in the scene. Notable Sonic 1 hacks are Sonic ERaZor and... well, everything else over here.

Zones

Green Hill Zone: The first zone of the first game has become as famous as you'd expect, with over 9000 remixes of its theme and other sorts of homages, including an appearance as a bonus level in Sonic Adventure 2. The boss - Eggman with a wrecking ball - has also become ubiquitous, with remakes appearing in Sky Sanctuary Zone in Sonic & Knuckles, X-Zone in Sonic Advance, and numerous fangames.
Marble Zone: One of two zones in the game that decides Sonic gaming shouldn't be all about speed, and thus makes you sit on a block for ages, likely causing you to fall asleep so that when you finally get to the other side of the enormous lava pool, you're not alert enough to jump off before the block descends into the lava taking you with it to your doom.
Spring Yard Zone: No Sonic game goes without a bouncy zone, and this is probably because this very first game started us off with them. Some people love these bouncy zones, some hate them.
Labyrinth Zone: Just like Spring Yard set the trend for bouncy zones, Labyrinth set the trend for water zones. It lives up to its name, though, especially in the later acts where the path certainly isn't obvious.
Star Light Zone: At first glance, this looks like a nice relaxing break before the final zone in the game. But oh, it'll still try its hardest to kill you with crushing stairs, bottomless pits and the robotic equivalent of suicide bombers.
Scrap Brain Zone: The last zone takes place in Eggman's factory. This zone was the only in the game to make significant per-act changes: act 1 has you approaching the factory, act 2 has you inside it, and act 3 takes place back in Labyrinth Zone when Eggman knocks you underground. There's also a so-called "Final Zone", but it's really just the small portion at the end of act 2, after you climb back up out of the labyrinth.