Green Hill
This time:
After Green Hill, I think Chemical Plant is the only other really obvious shoe-in zone in the game. Sonic 2 is still the series' best selling title, and Chemical Plant is its most iconic zone by a wide margin. Emerald Hill wasn't bad, but they were clearly trying to remake Green Hill and EHZ wound up being fairly unmemorable as a result. Being cleansed of even GHZ's minimal amount of difficulty didn't help either. Chemical Plant, though, that's where the game really took off. Starlight Zone had already introduced the idea of a speedy city/industrial level, but Chemical Plant took the idea and ran with it. No other classic zone beats it on sheer camera-busting speed, which makes the sudden aquatic deathtraps in Act 2 all the more memorable when that speed gets turned off.
Level Design
This is more like it.
Where Green Hill struggles to mesh old and new terrain, Chemical Plant strikes the balance between them excellently. Almost any level structure you could name from the original zone is back, from the curving pipes to the dizzying hills to that spot near the beginning where you can jump over a spring. At a couple of points it feels almost too faithful, but by and large it's a level that remixes the old ideas without leaning on them entirely.
One big benefit Chemical Plant has over Green Hill is that it
isn't an opening stage, and as such has a number of distinctive gimmick objects. Both of the zone's signature badniks are back (Spinies in particular being as annoying as ever), as are the revolving stairs, the bouncers, the transport tubes, the blue sphere chains, and the dangerously pink threat of Mega Mack. Missing in action are the moving platforms that formerly crossed the Mack, as well as the flip-up/flip-down segments of pipe. And frankly, I don't miss them. Both obstacles primarily served to dunk the player into the water, and Generations does that in ways that don't entail standing around for several seconds. In their place is the addition of slides (as seen in Labyrinth, Hydrocity, and elsewhere) and large boxes to roll through (as primarily seen in Green Hill and Angel Island).
With regards to the overall structure of the level, it's a much more elaborate affair than Green Hill before it. The routes branch at the start and fork further from there, crossing frequently with lots of vertical opportunities to swap from one path to another. As a result, the player is frequently given glimpses of other areas, brief flashes of possibility that beg for another playthrough to uncover their potential.
Chemical Plant is a great example of what constitutes a good classic Sonic level, one which really highlights why so many people loved the series in its glory days.
Art
A big part of what made the zone so striking in Sonic 2 is that it was this harsh, hazardous looking industrial environment positioned as just the second zone in the game after the luxurious Emerald Hill. The art that comprises the level design is reimagined in much the same way as Green Hill: a bit grittier, but faithful to the source material, if still somewhat large relative to Sonic. And then there's the background, which I can only describe as a labor of love. There's just
so much of it. A seemingly endless variety of towers, silos, and vats stretch into the distance, appropriately blending into the haze of the depth-of-field effect. Up close, an array of different walls, catwalks, and machinery cover the bottom half of the stage, making every area feel distinct. The effect is supplemented with a number of different colored lights, as well as the memorable pink hue of the Mega Mack. Special mention goes to the transport tubes, which have a unique shader that distorts everything they pass in front of. It's all exceedingly well done, a vision of the level that the original STI artists could only dream of.
It's unfortunate, then, that this variety seems to be the cause of the game's worst performance issues. The engine nearly grinds to a halt on multiple occasions trying to stream it all in, and this is an engine
designed to stream in large amounts of data to maintain high speed gameplay.
Music
Once again, the classic mix doesn't stray from its source material. I'm not sure that it's actually better this time, though. The original was loud and relentless and a bit muddy, but that was all part of its charm. Generations cleans the instrumentation up a bit, but the new drums just don't have the same impact and the whole thing feels slightly subdued in comparison.
Level Design
Much like Act 1, Act 2 really punches the complexity up a notch over Green Hill.
The initial 3D area is a great example piece, not just for why this is a much better level than its predecessor but for how Generations does things that the series hasn't dared to try in ages. You can run in a straight line through the whole bit if you really want to. More advanced players can nail a boost ring and a rainbow ramp to shave some time, but that's nothing new. The exciting part is that you can
jump off the rails and go exploring from the word go. The two paths curving around the main one are entirely solid and lead to both hidden goodies and the game's most devious shortcut. Or if you don't like that, you have the option to take a long leap off the main path and nail the back half of the shortcut on your way down to the abyss below. It's an exciting use of the full 3D space available in a way the series has always shied away from, given its historical difficulties with keeping the player from unintentionally flying off just one path.
The rest of the level mostly sticks to a simple high path and low path, with ample opportunities to fall from the former to the latter. It's much larger and more involved than anything in Green Hill, despite the basic simplicity; most of the gimmicks from Act 1 are still present in 2D and geared for modern Sonic's faster pacing, and his underutilized ability to boost across water comes in handy more than once. It doesn't feel anything like Act 1, but it does feel like Chemical Plant. Speedrunners will find multiple little deviations within both routes to save time. A brief 3D segment at the end is also interesting in that it repurposes the blue spheres in a rare instance of a 2D hazard coming to life in 3D platforming.
All in all, Act 2 isn't the most complex level in the game, but it's satisfying to run through and has plenty of payoffs for skilled play.
Art
It would've been easy to simply recycle the ideas laid out in Act 1 for a repeat viewing in Act 2. Sonic Team didn't do it the simple way.
There are the usual benefits of the 3D perspective present: Modern Sonic dashes across enormous pipes that rise and fall like rollercoasters, sprints past the towers and rides down the cranes that were just background filler to classic Sonic. It's all very exciting and striking. But Act 2 takes a step further and looks to answer a question: Why
is the Mega Mack rising? Because Chemical Plant is falling apart at the seams.
It begins innocuously enough, but about halfway through a klaxon sounds, emergency lights start flashing, and you just barely slide under a closing hazard door. From there on, everything changes. The towers and vats in the background are cracked, bent, and shattered, spilling waterfalls of blue and pink ooze into the depths below while columns of smoke rise into the air. The final stretch is a literal explosive finale, as the chemicals ignite and explode around Sonic, towers crumbling into pieces as he dashes by. It provides a real sense of progression and tension to the level, a flashy and bombastic complement to the 19-year-old terror of escaping the rising pink death.
Music
When I think of Chemical Plant, the word that comes to mind is not "slow". Jun Senoue has other ideas, however, as he's dropped the zone's high-intensity tempo down several notches. It isn't sedate and it isn't quiet, but I can't shake the feeling that there was supposed to be a higher intensity version for high speeds like Green Hill. It isn't
bad, but it's hard not to draw unfavorable comparisons with the blistering pace of the original. At least the lead synth isn't offensive, this time.
There's a nice effect present throughout the game for both Sonics that muffles the background music whenever they're underwater. It's set rather strong, though, to the extent that the music is almost inaudible. I'd like to see future games let up on the filter a bit.
