Sonic The Hedgehog 3: 1994
Sonic 3's first level is a paradise for a speedy hedgehog. It's got ramps that flip you through the air, spiky logs to traverse over deep water, lush vegetation with multiple layers of parallax scrolling – it's a vibrant, high-quality playground and a great introduction to the game.
But your first playthrough showed you so little of what the island had to offer. In fact, it kept its secrets so far up its sleeves, it took the release of a separate cartridge to bring them out again.
You see, Angel Island was designed to be played with Sonic, Tails AND Knuckles. With time pressing, Sega released the Sonic and Tails-only Sonic 3, before adding in Knuckles as a playable character with the bolt-on Sonic and Knuckles cartridge.
Knuckles' trademark digging ability opened up entire routes that were previously inaccessible, plus a new boss. Add in specific cubby holes that only Tails can reach with his flying ability and you've got one of the most well-developed and explorable levels in any platformer.
Other coolness of note:
It's also got one of the most impressive beaches in all of gaming – as Super Sonic dashes across the water at the start of the level, you get a brief glimpse of the sand, moving across the screen at different speeds to give the illusion of 3D. What an entrance.
Above: How many side-scrollers give you a glimpse of the world beyond?
It only takes one robot army and the whole place goes up in flames. It's all still playable, but it's never quite the same once Robotnik orders his minions to torch the place. After him, Sonic!
Above: (Clockwise from left) Act 1, its destruction and resulting inferno
The Secret of Monkey Island - 1990
Why's it so great? Because it's the settings for one of the finest adventure games ever made, that's all. It was beautifully drawn and animated for its time, allowing the story and characers to come to life like nothing else. And, being entirely fictitious, it could also house everything the story needed.
Above: Monkey head temple entrances, ghostly pirate ships... awesome
The original game's version would be good enough for this list, but there's been a current-gen remake, currently available on PSN and Xbox Live, bringing the game world to life like never before.
Unlike other islands on this list, you've got a very good chance of visiting a real Monkey Island. If this list on Wikipedia is anything to go by, there are some 14 real-life Monkey Islands. Feel free to set up a rubber chicken zipline on any that you come across.
Above: There are 14 different Monkey Islands worldwide
Other coolness of note:
You can't get stuck! Previous LucasArts games contained game-breaking event sequences that left you unable to proceed. Monkey Island never puts you in that position.
The island itself isn't the shape of a monkey. Or even a monkey skull. Fail.
Above: Guybrush takes in the wonders of Monkey Island