Many a player will pass by here in the transport spheres above, only able to gaze in wonder at this extra life, and be unable to backtrack to it afterwards. Not anymore. Just take the top, quicker route described in the previous point, and from the furnaces, hop across the platforms and elevator to the top, down the slope and through the spheres. Soon you'll encounter an oil slide to the right, and another to the left below this. You can get to that life by climbing to the top of this second, left slide. If you hold right as you fall, you should be able to run up to it anyway, but you can always try and jump up it too. At the top, drop down to the right, being careful not to land in one of those spheres, and there's the extra life, ripe for picking.

In this section early on in Act 2, you'll encounter a series of four green furnaces with lids, and no spikes. The first and third ones shoot up periodically, as per usual, but the second and fourth ones will only shoot up when you step on them, and both of these will each throw you upwards into a large tank, consequently springing you into a series of transport spheres that send you on a different route depending on which furnace you used. This is an important section, as it determines your course through the rest of the stage. The second furnace leads you on a detour up to the top left of the map from there, but then keeps you on the quickest route afterwards. The fourth furnace cuts out this initial detour by going straight up, but be sure to cross the first set of oil slides successfully, or you'll be tipped to the slower route at the bottom right corner of the map. Alternatively, you can skip both by hopping over all the furnaces and carrying on with this low, slow route to the far right. Point #5 informs you of an opportunity to switch to the faster one above, however. All routes meet up at Point #8.

If you're playing for fun, and up for a little glitching, there's also a trick you can try in this area. If you do the following, you'll be able to increase your speed and jump height for a while, not by making use of an intentionally placed secret, but a mysterious glitch, which I once read as being dubbed "Mega Sonic", back in the day. To get it, you need to get over to the fourth furnace on the far right, where the lid stays on it until you stand on top. Get on there, but at the same time, start holding right as you enter the tank above. There are some vertical spikes on top of a wall next to you, and what you want to do is move right so that you miss the transport sphere directly above, and collide with the spikes instead. Try and bounce off the spikes, into the transport sphere. It'll then throw you back down to the tank instead of to the right, like it normally should, and you'll probably end up squeezed into the tiny gap between the top of the tank and the right wall. There are some spikes there, so watch out, as you probably have no rings at this point. From there, either try and jump out and back to the floor, or sometimes you can actually walk through the wall to the right and fall to the path below.

There's a hidden spring along the route that began with the first furnace in Point #4. It's not the kind of thing you can stumble upon accidentally and the shortcut that it provides doesn't necessarily make this the quickest route, but it does offer some extra power-ups and it'll make your friends go "Wow, I didn't know that was there!".. If they care. Follow this route to the second set of transport spheres (the first set being the ones that took you away from Point #4). They'll take you to an area with two spiked objects moving back and forth on the floor. On the far, right side of these there's some gold decorative piping just above you, which conceals a vertical spring, if you can jump high enough onto it. This can take you up to the purple ledge, above the elevator on the right, which contains a speed-up item box. You can even use the spring to reach the next ledge up, if you leap on it from the left side and hold right, far enough. It's a slightly tricky maneuver, but at the far end of this higher platform, walk under the sphere and drop down to the next step for an invincibility item. Trust me when I tell you that you can then walk off of this step to the right and you'll drop down to an extra life, too! To the right of that is a blocked furnace thing whose spheres will transport you towards the end of the act.

Sooner or later, most routes bring you to this spot. Normally you would go left from here, towards a set of transport spheres that take you to the final stretch of Act 2. There is also an alternate, secret route to the end, which gives you 30 rings, plus an invincibility power-up, and begins on the platform directly above you (you can see it by looking up). To your right is an oil slide leading upwards, which is where the low route ended. Try and jump your way back up it to get to the top, squeezing underneath the large tank that's in your way. At the top, just drop back into the slide, in order to gain enough momentum to reach that upper platform. You also have to carefully use the right button as you're sent sailing upwards, when at the bottom of the slide, to ensure that you don't hit the bottom of the platform. It's tricky, but not impossible.

You'll find yourself with the choice of two ledges either side of the screen, suspended over the oil. Like in the Hill Top boss, Robotnik will come up through the oil, this time in a submarine-looking machine, but he won't stay up for nearly as long. He'll only rest on the surface, before popping back under again after a few seconds, so quickly jump down and give him as many hits as possible right from the get-go. Then, a long sharp-ended arm made of balls will fly out from the middle and arc over the surface of your platform, aiming right for you. Jump over the sharp bit, and the balls won't do you any harm. Next, another arm of balls will slither its way up from the oil pit, this one having a laser gun mounted on the top. At its full height, it'll wait a few seconds, then define your current vertical position, and fire a laser beam. For best amount of possible reaction time, make sure you stay right up close to the side of the screen. Then, it'll fire two more rather quickly, so stay on your toes. If it fires the third one while on its way down, it'll be in line with the platform, so this will actually send harmful shockwaves across the surface. Be prepared to jump over these as they come towards you. Then, Robotnik will briefly reappear at the surface of the oil, and the whole process will repeat until you give him the eight hits he deserves. The oil works the same as always so if you fall in, you can jump your way out.