The Marble Zone is an odd follow-up and contrast to Green Hill, both in structure and in flow. While Green Hill introduced the rolling landscape, wide open levels, and speedy sections that would define Sonic the Hedgehog, Marble is far more conventional. It starts with some smooth grassy hills, but it quickly transitions into a very tile-based landscape, like that seen in other platform games. The path is also quite linear, with alternate routes implemented as secret shortcuts. There is also very little opportunity to pick up speed, and none of the signature loops appear. Marble puts a heavy emphasis on methodical platforming. Perhaps this was deliberate to help ease players into this new style of platform game. Having a stage with such a conventional design so early in the game might have been expected to be easy for players coming from Super Mario Bros.
The hook, however, seems to be the way the stage transitions between ground-level segments and the underground “dungeon” parts, the latter of which makes up the majority of the stage. The depth in the background graphics returns in the above-ground areas, with lots of parallax scrolling. However, once underground, there’s only one flat background layer. It almost serves to emphasize the difference between Sonic the Hedgehog and what came before.
There are a lot more dangers here than in Green Hill, mostly in the form of traps that can crush Sonic, killing him in one hit. Spikes are back, as well, but the new hazard here is lava, which is actually slightly less dangerous than spikes because it doesn’t insta-kill you if you land on it from a recoil.
There is at least one new skill to learn in the Marble Zone: pushing blocks. The first encounter requires the player to push a block onto a switch to raise a platform. Sonic can’t continue unless the platform is raised, so the player is deliberately being taught what to do here. Pushing blocks comes into play several more times throughout the Marble Zone, and it’s implemented in different ways, so it turns out to be a worthwhile gimmick.
In a few instances, Sonic needs to push a block into a pool of lava, and then stand on it as it floats to the other side. Incidentally, it was during one of these times that I saw Sonic’s idle animation for the very first time. Having Sonic break the fourth wall by looking directly at the player and tapping his foot was a cool way to emphasize his personality, especially in 1991.
The only other “skill” presented in Marble Zone is jumping on switches to activate pillars or platforms. Not terribly exciting, but it shows up again later in the game, whereas block-pushing is limited only to the Marble Zone.
In Act 2, Sonic must push a row of blocks so that he can drop down into a narrow corridor, which then activates a flow of lava that chases him. This could perhaps be seen as the first instance of a setpiece in a Sonic game; another element that would define the series in the future.
Once Sonic reaches the end of Act 3, another boss fight begins, and once again, it’s with Dr. Robotnik. It’s interesting that Robotnik is the only boss in the game and that you fight him six times. This mirrors the original Super Mario Bros in which you fight Bowser at the end of every world. However, while Bowser didn’t change much from fight to fight (difficulty came more from additional environmental hazards), Robotnik always shows up in a new contraption and with a new attack pattern. This time, his Egg Mobile simply drops fire onto the two platforms at either end of the screen, forcing Sonic to jump from one to the other. The lava pool between them spurts fire, making the jump more hazardous. The Egg Mobile is always low enough to reach with a jump, so attacking him is easy, but unlike the previous boss fight, there are no safe spots, so Sonic must constantly avoid danger.
Another eight hits, and the Egg Mobile explodes, causing Robotnik to fly off once again. With the oddly conventional Marble Zone behind us, we’re off to the Spring Yard Zone, and a return to level design and gameplay that is very distinctly Sonic.
Screenshots captured from a longplay video by RickyC.