There's a variety of backgrounds and scenes throughout the level, moving from mountain tops to frozen caves to a huge Arctic sea, so lets start at the top. As Sonic, you'll hit the white slopes with style with the first appearance of the snowboard. Not that you'll have much time to look around, but the scenery here is a mass of misty mountains, all white and light blue, and rocky in appearance. The sky is a dark blue colour, which the rows of rocky mountains gradually fade into as they get further into the distance, and there's a floor of thick white clouds below. You'll then come to the ice caves, where closer walls behind the character are made of diagonal patterns that glow from blue to purple continuously. Get into an open area and you'll see them in their true glory, as huge dark blue icy cylinders expand the entire height, surrounded by endless waves of shorter crystals, the pointed ends of some of them glistening in what little light illuminates them. It's somewhat reminiscent of Superman's Fortress of Solitude, although obscure circular fire-alarm-like things glowing from blue to purple is a feature of it that I never quite worked out. At one point, holes appear in the wall of the cave, where you can see huge rows of large crystals in the lighter distance. When you finally break out of the caves and first reach the icy river at the end of Act 1, it's initially nightfall, but you can see huge blue ice bergs on the horizon, with smaller ones in front, sitting on a freezing cold sea. Closer to you, parts of the ice sheet that covers the water have broken up and are floating seamlessly across the screen. It's lightly snowing too, until you beat the Act 1 boss, and morning suddenly arrives on the scene, beautifully crisp and clear. Strangely this means the whole level goes from day, to night, back to morning again all within the space of a few minutes. Still, let's not hold that against it. Act 2 is then a mixture of this morning landscape and more caves, which appear similar, but a bit more open this time, across a big room filled with icicles.

I think it's safe to say that no where else will you find two such different acts in a level, with regard to how they're structured. Act 1 is a very enclosed maze of thin corridors and loads of long, steep sloping drops, embedded deep within the caves, with a few slightly larger rooms thrown in for good measure here and there. Unlike similar stages, however, these paths aren't really compressed together to conserve map space, so they'll be taking you on fairly long distances, rather than short, multi-directional routes. One trick Act 1 does have up its sleeve and uses continuously is vertical looping, where you can drop down a pit at the bottom, only to reappear at the top of the map without even realising. This is used several times to create the effects of endless pits, where your character will fall continuously over and over again down long shafts, until you can make it to a platform or complete whatever task you need to do to progress (all detailed below). Aside from these constant drops, however, the passages will usually be taking you right. There are tonnes of slopes, most being exceptionally steep that your character will just slide down, and it's impossible to climb them back up, but between these are largely flat areas and a series of large platforms containing all the hazards to deal with. Act 1 has few multiple routes for Sonic and Tails, except for one small shortcut, though Knuckles manages to find a different, exclusive route on a couple of occasions, thanks to his ability to destroy tough ice blocks, and his Act 1 boss takes place in a different area.

Item boxes, springs and buttons across the level, and sometimes nothing at all, are all usually contained in a little ice block that needs to be broken with a jump before getting to the goods, unless you're Sonic, who can open the item box inside the barrier by using his double jump insta-shield, which is a neat time saving trick. Spikes are a bit different in Icecap as well, and constitute small icicles that are either spread across the ground in long pits, or hanging from the ceiling, some of which are ready to fall on your unsuspecting head on rare occasions. Over the long pits on the floor, some huge icicles can hang from the ceiling amongst the smaller ones, and will drop down into those on the floor, so obviously don't get caught underneath, but when they're lodged in there, their tops can act as stepping stones for you. Also notice the semi-circular groups of sharp icicles that fan out across the walls. They may look curious, but they're not worth investigating. Knuckles must glide around several smaller airborne ones sitting stationary in the middle of one particular large room in Act 1. When faced with a large segmented vertical barrier blocking your way, notice that it may consist of four blocks stacked up on top of each other, and the bottom one can be destroyed with a spin dash. When you do this, the rest will fall down one, and for Sonic or Tails, the top block will come down to a level where you can jump on top, using it as a platform to get to the next ledge. Sometimes you just need to get through to the other side though. Knuckles will need to spin dash the second block as well if you want to get him to the top of the stack. If you take out all three lower blocks, the top one cannot be destroyed, but to bring them all back, leave the area and then return. With a slightly unsurprising presence in this first ever ice level, watch out for the freeze-guns found on ceilings, because if you stand beneath them for too long, their blast of freezing air will conceal your character in their own block of ice. Unless Tails can free you in time by jumping on top of it or spin dashing (don't bet on it), the block will explode after a few seconds, taking your rings or shield with it. Some ledges will break under you weight, but certain pieces of floor that you need to get through won't collapse until you hit the fairly obvious button right next to them.

To get up long, wide shafts, you need to make use of a series of swing-able platforms that sit next to ledges, attached by a green chain on the ceiling just above it. When you see one, run into it with speed, via spring or spin dash, and it'll swing upwards on the chain. If you were fast enough, it'll swing around 180 degrees, taking you up to its highest peak where you can jump off to the next bit, but be quick before it comes back down again. At the end of Act 1, the final one will fly off of its chain, and into an adjacent corridor. There are numerous long crushing blocks around. Some drop and recoil continuously, while others on the ground sit there until you step on them, and then move upwards trying to squish you into the ceiling before returning back down again. Similar ones can act as closing doorways, coming down after you've passed by. As Sonic and Tails, there are some that won't budge until you hop on a large sliding platform that can be dislodged from its perch (see Points 2 and 6 respectively). It'll then tumble down the slopes with you on it and crash straight through these barriers before being destroyed when it comes up against a solid wall. Knuckles meanwhile, may be able to smash through these tough barriers automatically using his naturally swinging fists. However, Knuckles will also find that one or two have been placed to block off Sonic's normal route from him, and even he cannot destroy these.

In Act 2, run or spin through big mounds of snow that will otherwise slow you down when you walk through them, and you can jump on purple trampolines, attached to walls or small blocks by green chains to bounce your way up higher. If you can't get enough height on the first bounce, fall back down and keep going, but the chains aren't solid so if you miss the purple trampoline, you'll fall right through the chains. Also keep an eye on Tails, because he tends to interfere with your bouncing rhythm and bugger things up for you, although he can also add to your height considerably, when bouncing at the right times. On the water at the very bottom of Act 2, you'll need to hop across platforms that float on the surface. These will slowly drop downward with your weight, and because there ain't much but instant death awaiting you further down, it's best not to hang around on them. Like in Hill Top Zone, when you go through the loop-de-loops, you may need to break through the floor at the bottom to get into a tunnel that usually takes you into the caves below. To make sure you break this floor, hit the down button to start up a spin while zipping through the loop.