When playing Sonic 3, did you wonder why there were rings that weren't accessible? where had Robotnik's Death Egg crashed? what happened to Knuckles at the Launch Base? Well, wonder no more because you have your answer inside Sonic's best 16-bits adventure: Sonic 3 and Knuckles.

Graphics: 9/10

This game is HUGE – 34-bits according to Sega. This shows in the graphics.

They are a notable improvement from Sonic 2. Both Sonic and Tails and better-drawn and move more fluidly, both in the traditional left-to-right fashion and all around. Indeed, in Angel Island Zone, you can grab vines and go 360 degrees. In Hydrocity Zone, there are cylinders going up and down and turning on themselves, making you see all around the characters. Sonic and Tails' drawing is also much better inside Special Stages. They are in 3D like Sonic 2, but there is no lag when they are moving. Finally, Knuckle's drawing is also well-done. His special abilities (gliding and climbing walls) is done well and he can move 180 degrees with it, making you see his face in the process. However, I think his head is a little too square inside the Special Stage.

Each zone is very beautifully designed are better-drawn than in Sonic 2. In Angel Island, the first part has nice palm trees and tropical setting, whereas the second part (which was set on fire) has a blazing background. Hydrocity has water all around (including in the background) and there are many water fiends making your life difficult. Marble Garden has marble columns all around, Carnival Night is brighter and shinier that Casino Night (there's even a part where Knuckles shuts off the lights), the Ice Cap has snow and ice everywhere (although it's not slippery as it is in Mario Games) and the Launch Base Act 1 boasts a very beautiful image of the Death Egg (you also see it fly at the start of Sky Sanctuary). Mushroom Hill has bouncy mushrooms, Sandopolis has quicksand, hieroglyphics and heat that makes the background a little blurry, the Lava Reef has lava all around (yay for fire shield) and the Death Egg shows both the ship's circuits and the Earth below. The Flying Battery, Hidden Palace and Sky Sanctuary zones weren't as well-drawn – the background wasn't as detailed – but were better than Sonic 2 nonetheless.

Finally, Robotnik's machines (mid-act and end-of-act) are nicely drawn but also well-adapted for the zone. Angel Island and Lava Reef shoot fire, Hydrocity play with water, Carnival use the neon's energy to generate electricity, Ice Cap swirls ice and tries to freeze you and the Sandopolis had both quicksand and an ancient machine trying to crush you. Special mention for Marble Garden, where Robotnik actually flies into the background, the Hand at the end of Lava Reef that comes in front of you and Robotnik's ultimate creation in Death Egg 2, whose core is in the background before it starts trying shooting deadly Super Emerald beams at you.

Special mention to the Ice Cap, where Sonic starts on a snowboard and zips past trees. Watch out (seriously) if you're prone to seizures as Hyper Sonic (when you collect all emeralds from Sonic 3 and Sonic and Knuckles) flashes in an unusual manner.

Music: 10/10

Along with beautiful graphics, Sonic 3 and Knuckles has an outstanding soundtrack.

For each act except Lava Reef, all second acts are a remix of act 1 and I thought it was a good idea. It gives a feeling of continuity unlike Sonic 1 and 2. Also, the music sounded well-suited to my ears. Angel Island sounded very exotic and tropical, Carnival Night sounded like a real carnival (and act 2 sounds almost like act 1, unlike other zones), Sandopolis has an oriental beat to it and Death Egg sounds very modern. The Launch Base music sounds serious and intriguing, hinting about something big happening, Sky Sanctuary sounds strangely epic (but sounds good all the same) and the mid-act boss theme sounds a little less goofy than in Sonic 3 (and has no wooden shoe tap dancing). Finally, Knuckles' theme is a little more elaborate without the wooden tap shoes.

Now, as unimportant as they sound, sound effects are important, and they are well-done in Sonic 3 and Knuckles. The springs sound bouncier, the shields' special attacks sound appropriate (fire/electric attack, water bubble bounce) and bombs (like Robotnik's preview boss at the end of Angel Island 2) sound realistic enough, with the whistling and all. Also, getting an emerald sounds more triumphant as the sound is a decrescendo. Finally, rock-breaking actually sounds like rock-breaking (and there is no lag like Mystic Cave's falling bridges)

Slight negative: the one-up sound was better in Sonic 3. Big plus: the end-of-game mix of all the tracks is better done than Sonic 2.

Addictiveness: 9/10

Thirty-four bits of video game is enough to keep you hooked up, and it's not only about the music.

All zones are huge and have plenty to explore. Unlike previous Sonic games, Special Stages are completely hidden and you will have to search carefully to find them. Granted, some are very easy to find, like Angel Island 2's very first one, at the end of the tunnel you go down of at the very start of the act. One-ups are also well-hidden; fortunately, you get Tails' help when he flies you up for those hard-to-reach spots. On his side, Knuckles can reach those places by climbing walls.

Crossing lampposts with a certain amount of coins still produces a star circle you can jump in. Depending on how much you have, you can jump in a slot machine and earn (or lose) coins like in Sonic 2 (although winning the jackpot doesn't create lag); a gumball machine where you can earn coins, a shield or a life; and a magnetic sphere stage where your earnings can increase quite a bit; try reaching the top if you can!

Story: 10/10

Yes, I put “story” because this game is really one continuous stage divided in several acts. Unlike Sonic 1 and 2, acts are not independent from each other. Since Sonic 2's Sky Chase Zone, everything acts have been logically following the other. Even Donkey Kong Country couldn't achieve such continuity.

At the start of Sonic 3 and Knuckles, Tails is still piloting the plane and Sonic, still on his Super Sonic energy, which he loses when he gets knocked by Knuckles. After crossing Angel Island, he fights Robotnik in front of a waterfall and gets drop to Hydrocity. After swimming through, you get blown off to the Marble Garden. At the end of the act, the sun sets and Sonic and Tails  fly to the Carnival Night (the best transition). After partying, a canon shoots them to the Ice Cap, after which a tunnel leads them to the Launch Base.

After Robotnik's failed attempt to Launch, he crashes on the Mushroom Hill. Once Sonic foils his plans, he flies away in the Flying Battery (the Wing Fortress?). After foiling Robotnik's plans, Sonic then lands in (literally; he lands in the sand) the Sandopolis. After crossing the desert and the pyramid, Sonic falls into the Lava Reef where (before the boss of act 2) he falls right under the Death Egg engines. After beating Robotnik, the lava clears, revealing the Hidden Palace. After Robotnik steals the Power Diamond from Knuckles, Sonic teleports to the Sky Sanctuary. After defeating is metal nemesis, he narrowly escapes the crumbling of the Sanctuary and jump in the Death Egg. If Super (preferably Hyper) Sonic is in the team after defeating the Death Egg, then he uses the power of the emeralds to try and defeat Robotnik once and for all. When you do, you slowly fall back down on Tails' plane and give the Floating Island the name it deserves – the Power Diamond, when fully charged, activates the island.

Depth: 10/10

As I've shown in story, Sega managed to put up a very long and logical story to show Sonic's fight against the evil Ivo Robotnik. All zones (except after Lava Reef, since you don't have any Special Stages to look for) are gigantic and have a lot of treasures to be found.

But that's not all. The original Sonic and Knuckles cartridge could be opened and mixed with other games. By putting Sonic 2, you can play as Knuckles through the entire game. He can glide and climb walls (finding hidden one-ups), and when you get out of Special Stages you keep all your coins (but not your shield).

And when you put Sonic 1 (and pressed a+b+c+start), you could access a whole universe of Special Stages. It's seemingly infinite; I think I made it as far as stage 100 (a FAQ says there are 128). You can take the long way and do them all or get the perfect and skip 10 stages.

Difficulty: 5/10

In many ways, Sonic 3 and Knuckles is much easier than Sonic 2.

Compared to Sonic 2, you can restart your game at the last zone you died in keeping all your emeralds. And compared to Sonic 3, you can keep you lives (to a maximum of 99) and continues (maximum 14). Once you reach the Hyper Sonic Stage, touching the Big Rings give you 50 coins. Probably thanks to your shields, you need to double-jump without one in order to become Super/Hyper Sonic.

Speaking of shields, they can protect you from certain attacks (fire with fire, electricity with lightning. Be warned that opposite elements cancel out; getting in water with fire/lighting shield will put them out). That makes boss fights in Angel Island, Carnival Night, Mushroom Hill, Flying Battery and Lava Reef very easy. The lightning shield is a coin magnet so you can enrich yourself easily. Finally, each shield can make you reach high spots (especially the lightning shield), and the bubble shield give you air underwater. You also keep your shield when getting out of Special/Bonus Stages.

The Special Stages are also easier in Sonic 3 and Knuckles. They have less lag than Sonic 2 since you are on a small planet rather than an open-end half pipe. It's much easier to map the Stages, making it easy to get the emerald. The main challenge is to get all the rings (and therefore a 50k pts bonus); blue-colored emeralds are the hardest ones on that matter.

However those stages can be a challenge. The star balls make you move in reverse, putting you at danger to hit a red sphere. Also, the Sonic and Knuckles emeralds have yellow spheres that make you jump ahead; make sure to know where you are landing! Plus, the running accelerates the more time you spend in the stage (and the music accelerates accordingly). Fortunately, you can press up and start before you would normally.

In addition, if you are a completion geek, finishing the game with Tails or Knuckles will be challenging. Knuckles jumps less high than Sonic or Tails, making him follow inferior roads like in Angel Island. However, his ability to break rocks can reveal otherwise inaccessible secret passages. On his side, Tails only become Super with the Super Emeralds, making the way until Mushroom Hill hard. Also, the Marble Garden boss is also fought flying, but you can only hit it from under. That was quite a challenge for me at the time. Fortunately, Super Tails compensates his lagging behind by having Flickys (little birds) flying around and hitting enemies. Finally, since both have special abilities of their own (they can't use fire attack), they become Super/Hyper when they double-jump.

In short, Sonic 3 and Knuckles is a must-try for all video games nostalgics. It's huge, it's colorful, it has  a lot to offer, has an addicting soundtrack and offers four different ways to complete the game. And since you can save your game, don't worry about not completing it on the first try like Sonic 1 and 2. Finally, its lag-free two-player mode, completely different from the regular and which also offers time trials, will keep you busy for hours.