Act 2 carries a number of visual differences, with a whole new, much more colourful and vibrant background. The huge pillars are now more detailed and all the bricks seem to glow, reflecting a brighter purple light from underneath. There are a number of different vertical levels in the background, each supported by the pillars and dark windows can be seen further behind. The top level appears much darker and further away. There are now also rope bridges to cross, and long, winding water chutes that are bright blue and have little glass covered sections. Also look out for the little extra graphical touches such as the occasional drop of water falling from ceilings.

Act 2 has a few substantial differences regarding the way its been arranged, but an emphasis on both long curving loops and tricky platform-hopping puzzles remains. One of the main differences is that the speedy sloping roads are now replaced by long blue water chutes. These twist and twirl up down and around, and you often have to use a speed-boost object to spin your way up them when they meander up a thin vertical passage. The layout tends to be more enclosed in this act, and while there are very big open spaces as well, these are mainly used for the water chutes as they tip you down a long diagonal stretch, dumping you in the water at the bottom, where you'll run across the surface. You'll also find three or four tall rooms that you are thrown up into from a speedy path in the water below. Typically in these instances, the quickest and often safest shortcuts are found at the top. If you don't make it that far and fall back down, a series of snaking black platforms can deliver you back up, or through the full route to the right. In most other places however, you'll find yourself working your way through narrow horizontal corridors and in particular, long vertical shafts, making use of the various platforms and fans to get you to the top of them. There are brief shortcuts every now and then, more easily accessible with the ability of flight, but there is largely only one main route through the whole act this time. Not only that, but this long route abandons the basic right-ward direction and weaves back and forth and up and down all over the place, using up just about every bit of available space on the map. Though there are lots of new hazards to watch out for (including a large crushing wall hot on your heels at the beginning), the good news is that there's less water to deal with in this one, with most submerged sections consisting of little more than a quick dash along a water chute.

On top of all that, Hydrocity has an absolute tonne of badniks to piss you off from start to finish. There are six of the little robotic buggers to contend with, both aquatic and otherwise. Pointdexter are blowfish badniks that move back and forth slowly over a set area underwater. Spikes emerge from their shells periodically, at which time they cannot be damaged. Turbo Spiker are red snail bots with a spike-covered shell diagonally mounted to their rears. Get near, and it'll fire off with rocket power, at which time the badnik then begins to quickly dash back and forth across the ground. In Act 1, immobile Blastoids sit on thin ledges, firing projectiles from their diagonal cannons, three at a time. The part of the ledge they're sitting on will only give way when you destroy the Blastoid, allowing you to continue (often to another one below). They can also be found on various other ledges where destroying them won't be mandatory. If you happen to be wearing a shield at the time, the projectiles will just bounce off of you, but try and jump over their line of fire during a break between rounds, and go for him then. Watch out for the Mega Choppers; they are small, but being based on piranhas, they are also extremely dangerous. Underwater, they swim towards you and latch on, during which time, you cannot jump or roll, and what's worse, one by one your rings will start to deplete until it sucks them all out and kills you. The best remedy is to quickly move left and right to try and throw them off. Bugernaut are weird dragonfly things that hang out in "families", and act like Sonic 2's Whisps, and just generally badger and pester you when you get near. I say families because there's usually two together, and they're accompanied by little baby Bugernauts whom you cannot kill, but just fly away once you've made scrap metal out of their parents and orphans out of them, heartless beast that you are. Last but not least are shark bots named, appropriately enough, Jawz. These can exist above water as well as under it, and just fly towards you, from the side, though usually in groups. Interestingly if you run into them, aside from getting hit yourself, they will also explode, but without producing the little trapped animal inside, who has presumably met his grisly death in the explosion.

- Hydrocity Zone is the only Sonic level to be named in the music video of a British pop song. Yes, that's right. Wonderman, by Right Said Fred was a 1994 release as part of the promotion for Sonic 3 in the UK, and the video is interspersed with a few short glimpses of the game in action. The band themselves are hanging out in a dark factory area that is signposted as Hydrocity Zone, despite appearing nothing like it at all. Think I'm making it up do you? Catch all the madness here.

It came in at #55 in the charts for one week. Oh.