Sonic must defeat doctor Robotnik yet again. This time, Robotnik wants the Master Emerald, the biggest and most powerful of all the Chaos Emeralds. With this emerald, the Death Egg, Robotnik's ultimate weapon will have limitless power and nothing can stop him from taking over the world. It's up to Sonic to stop Robotnik's plans, but he's not the only one. Knuckles, guardian of the Floating Island and the Chaos Emeralds tries to stop him as well.

Play as both Sonic and Knuckles in 8 new zones in two different adventures. Get as many rings as you can, get all the emeralds and defeat enemies. You can combine this game with Sonic 3 to play the game as it was meant to be played. When combined with Sonic 2 you can play it with Knuckles for a new game experience.

This is the one video game that I think captures the essence of a speed junkie’s highs and lows. When you’re high, you’re flying so fast so can’t catch breath. But when it’s time to slow down, the panic sets in. S3K features numerous moments of moving walls and collapsing ceilings, crumbling backdrops and closing walls. And the timer, almost completely useless in the first two Sonic games, looms over your head from start to finish; those large worlds guarantee you’ll often run out of time before reaching the exit or defeating the bosses. This tension is one of the game’s calling cards.

Sonic & Knuckles is blessed with some of the finest and intricate level design, and this is the balance that truly makes the game great. There’s the obvious Mario influence in the way surprises and rooms are hidden away, but now they are plentiful enough to actually justify all that wandering. You are amply rewarded for your curiosity, with its secrets and multiple pathways, and that’s what keeps you coming back again and again. You could run through the various zones several times and still not take the same exact path twice.

The enormous size of the game worlds allow for some truly amazing speed runs, torpedoing through loops, twists, turns. There are eruptions of water, deep, pummeling vertical drops, snowboarding down mountains, elevator cars run amok, runaway spinning tops. One of my favorite moments are the “racetrack timers” in the Death Egg Zone, which grab Sonic and hurl him in chaotic loops through open space. It’s completely gratuitous, of course, but a terrific rush (and clearly predicts Nights).